Abstract: Objective To calculate the unit cost of antiretroviral treatment（ ART） of HIV /AIDS cases and to provide data for scientific budget planning and resource allocation of HIV / AIDS prevention and control. Methods Bottomup method was used to collect the cost data of HIV / AIDS ART. The unit cost was split into various sub-additive ones. Field observation method and key informant interview were used to collect related data on the cost of ART and every subcost was measured to estimate unit cost and its composition. Results The unit cost was calculated according to classification of ART drug and whether the patient was a new enrollment or having previous treatment. In the group of first-line drugs and drug combinations using nevirapine,the median unit cost of a new enrolled ART patient and a previously enrolled patient were 5 907. 46 RMB yuan per year and 3 598. 89 yuan per year,respectively. In the group of first-line drugs and drug combinations using efavirenz,the median unit cost of a new enrolled ART patient and a previously enrolled patient were 8 471. 22 RMB yuan per year and 6 162. 65 RMB yuan per year,respectively. In the group of combination of second-line drugs,the median unit cost of a new enrolled ART patient and a previously enrolled patient were 13 275. 30 RMB yuan per year and 10 966. 73 RMB yuan per year,respectively. Drug cost and related test cost accounted for more than 90% of the unit cost of ART. Conclusion The main influencing factors of unit cost of ART are drug combinations and related test fees.