Objective To investigate the reactivation effect of nicotinamide (NAM) on latent virus in SIV/ SHIV- infected monkey CD4⁺T cells. Methods Peripheral blood from five SIV/ SHIV-infected rhesus monkeys was collected with undetectable virus loads for at least half a year. CD4⁺ T cells were sorted and treated with latency-reversing agents accompanied by monitoring of viral loads in supernatants and changes in activated T cell surface markers and coreceptors CXCR4 and CCR5 on CD4⁺T cells. Changes in nuclear antigen SIRT1 were detected by Western blot. Results NAM had a good activation effect on latent virus in SIV/ SHIV-infected monkey CD4⁺T cells and reached a higher level combined with GS-9620. This did not cause extensive activation of T cells and had no influence on CCR5 expression, while CXCR4 expression was slightly upregulated. NAM significantly reduced expression of nuclear antigen SIRT1. Conclusions NAM is a good choice for a latency-reversing agent.