In this paper, an improved Lsb (Least Significant Bits) information hiding algorithm is proposed according to human visual theory and implemented in the temporal-spatial domain by using C#, and based on this, a system is developed for hiding and extraction of multimedia files, Compared with the traditional LSB method implemented by Matlab, the improved one has obvious advanlages in the environmental confguration requirements, the time-consuming in running and ease of use, To be specific, the system realized on, net platform takes less running time and resouces, has better extensibility and greatere ease-to-use, and other distinct features Besides, the system developed for hiding and extracting multimedia files based on the method has a wide range of adaptivity and good applicability.