Joint Detection technology is a hot point in the research of TD-SCDMA system. Because of a SNR degradation, JD can not reach the need of system performance when system loads is close to the spread factor. MSJD and iterative multi-user detection are put forth to overcome the problem. When iterative MUD is adopted, the research shows that system performance is close to single user performance after 3 iterations, but its computational complexity grows exponentially with the number of code channel. When MSJD is adopted, complexity is reduced compared with iterative MUD, but system performance of code channels numbered K is only close to system performance of code channels numbered K/2 as JD is used. Considering computational complexity and system performance, multi-step iterative multi-user detection technology is brought forth based on iterative MUD and MSJD. According to simulation, the result can be concluded that complexity is reduced compared with single iterative MUD and system performance is improved compared with single MSJD.