Objective To establish a new dynamics model of HIV/AIDS spread, and to explore HIV/AIDS transmission law in a specific region. Methods The HIV-infected individuals were divided into the confirmed group and the undiagnosed group.The undiagnosed group was the main source of HIV spread. According to the theory of survivorship bias combined with the efficiency of HIV transmission and basic reproduction number, a dynamic model of HIV spread was established and its stability evaluated.Results The results proved that the susceptible-infected dynamics model of HIV/AIDS spread had a better stability, a...