A kind of new nano composite with ultraviolet (UV) ray resistance and high temperature stability was prepared by in-situ polymerization in low temperature. Polysulfonamide (PSA) was synthesized with 4, 4-diaminodiphenyl sulfone (DDS) and terephthaloyl chloride (TPC) in the common solvent N, N-Dimethyl- -acetamide (DMAc). Nano filler is a certain nano titanium oxide modified by silicon oxide (TMS), which plays the role of UV resistance additives. Properties of the novel composite materials were characterized by Atomic Force microscopy (AFM), thermal gravimetric Analysis (TGA) and Ultraviolet Spectroscopy. AFM had showed the sizes and distributions of TMS particles in the nanocomposite. Ultraviolet Spectroscopy for the nanocomposites showed a large absorption in UV band. TGA showed the decomposition temperature was increased over ten degrees with 0.5% wt TMS for this nanocomposite compared with pure PSA.