Objective To explore the characteristic changes of SHIV-XJ02170 during serial passages in Chinese rhesus macaques in late infection stage and to identify the sequence variation of env gene. Methods Viral bloods from macaque G0401V infected with SHIV-XJ02170 in late infection stage of 5 years were used for passaging 2 monkeys (G0401V→G0402V→G0403V)without CD8 + T deletion and 1 monkey ( G0401V→G0404V) with CD8 + T deletion. Flow cytometry，viral load detection and sequence alignment were used to analyze the change features during serial passages.Results SHIV-XJ02170 incubated in G0401V showed stable infectivity during late infection for 5 years and its virulence was enhanced after passaging in vivo，especially after CD8 + T cell deletion by injection of CM-T807. G0402V showed a sharp decline of weight and CD4 + T cell counts in peripheral blood，and died suddenly on day 41 after infection.Monkeys G0403 and G0404 showed a viral load peak on day 14，then maintained low viral load level (104 － 105 copies/mL) up to now after passaging (141 d) . Sequence alignment analysis showed significant variation in env region and changes of Nglycosites in gp120 region. Conclusions The infectivity of SHIV-XJ02170 is significantly enhanced during serial passages in vivo and this study provides a firm basis for SHIV-XJ02170 infectious molecular clone construction.