Characteristics of small-scale turbulence are considered of fundamental importance to understand the nature of turbulence and structure function is one of the most widely used quantities to study small-scale properties of turbulence. In this study, small-scales statistics, mainly, in terms of structure functions and partly by de-veloping filtering techniques are investigated from experimental and numerically simulated turbulent flows.Streamwise evolution of longitudinal and transverse structure functions in nearly isotropic decaying channel flow is examined at four downstream locations for Reλ up to720. At first, some low-order reconstruction relations between longitudinal and transverse structure functions are investigated in the light of recently derived relations and it is shown that the low-order transverse structure functions can be well approximated by longitudinal ones within sub-inertial range. On the basis of theoretical arguments, it is found that reconstruction of fourth-order transverse structure functions with recently proposed relation by Grauer et al. is less valid as compared to the previously derived relation by Antonia et al. Secondly, both, ESS and direct methods are used to measure the scaling exponents of longitudinal and transverse structure functions at streamwise four locations. It is observed that both longitudinal scaling exponents ζL(p) and transverse scaling exponents ζT(p) showed departure from K41scaling and ζT(p) are more intermittent than ζL(p) and the differences of scaling exponents between four measured locations is small ex-cept the last location. It is found that ζL(p) measured at first location are very close to the predictions of Zybin et al. and those measured at last locations are close to S-L model. No obvious trend is found for the streamwise evolution longitudi-nal scaling exponents, whereas, in contrary, transverse scaling exponents become slightly smaller with the development of steamwise direction. The stremwise varia-tion of the order-dependent isotropy ratio indicates the turbulence at last location is more close to isotropic than the other three locations.Hierarchical structure parameters, proposed in She-Leveque model, are investi-gated for both velocity components obtained from four different flow types over a large range of Reynolds numbers:255<Reλ<720. The values of longitudinal component βL are observed nearly same for all four types of turbulence and close to the theoretical value. The values of transverse component of β are also found very close to each other. The parameter γ, for streamwise velocity components is nearly the same but significantly different for vertical components in different flows. It is also observed that for both parameters, an obvious relation between the longitudinal and transverse components βT<βL (and γT<γL) always hold. However, for all four flows, we found very small but non-vanishing difference be-tween βL and βT.It is noticed that at low Reynolds numbers, the deviations from K41scaling are mainly due to the γ and slightly because of the β. However, at higher Reynolds numbers the deviations seem as a consequence of γ only. Over-all, the study suggested that the hierarchy parameter β may be considerd as a universal constant.Finally, multi-scale properties of Reynolds stress in decaying channel flow with high Reynolds number are investigated. Two filtering techniques i.e., zeroth-order and first-order detrending method are applied to the two velocity components, where the local mean value (resp. local linear trend) is removed in the former (later) technique. Some basic statistics for thirty measurements show that the variation is very large at first two locations and relatively small at last two loca-tions. Moderately good power-law is found for the mean value of local Reynolds stress at last three measurement locations with scaling exponents approximately being1.0and a dual power-law is observed for the mean value of standard deviation of local Reynolds stress at all four measurement locations with scaling exponents being0.53and0.58for zeroth-and first-order filtering respectively. Present results about local Reynolds stress are useful to build and evaluate the model of sub-grid Reynolds stress in Large Eddy Simulation.