Strong-field photoelectron spectroscopy encodes temporal and spatial information about both the electron and the ion dynamics.To extract this dynamical information,one needs a full understanding of the physical mechanism underlying the complicated interference structures in the photoelectron spectrum.We developed a GQTMC method which could apply to arbitrary values of the Keldysh parameter.Our simulations agree well with both the experimental and TDSE results.It provides an efficient way to probe the interference structures and the underlying electronic dynamics in photoelectron momentum distribution.