In this manuscript, the dynamic behaviour of a nonlinear HIV/AIDS dynamics model using HIV infected population is proposed. Here, we divide the HIV infected population into two subclasses: the tested and untested HIV infected populations. The novel part of the model is that when susceptible population interacts withthe untested HIV infected population, the susceptible population is shifted to untested HIV infected population. Otherwise, it is transferred to tested HIV infected population, while many researchers have taken this infection astested HIV infected population. For infection-free equilibrium point, we determine the basic reproduction number and explore the existence and local stability of equilibrium point. For two endemic equilibrium states, we investigate the positivity and stability of equilibrium points and determine the conditions where it exists. The Routh–Hurwitz criterion and Bellman and Cooke’ theorem are used to establish the stability of the non-infected and two endemicequilibrium states. Numerical simulations for all equilibria are also carried out to examine the behaviour of the system in different dynamical regimes.