To address the issues of low thermal efficiency and poor economy in the ocean temperature differencedriven ocean thermal energy conversion (OTEC) system, OTEC combined with air conditioning (OTECAC) test system was designed and built.The system utilizes the cold energy of deep seawater in a graded manner by generating electricity and then cooling the air, thus significantly improving the conversion efficiency of ocean temperature difference energy. Performance evaluation metrics such as expansion output power,refrigeration capacity, and overall thermal efficiency were defined based on thermodynamic principles.Experimental tests were conducted to analyze the performance variations of the OTECAC system under different operating conditions. A comparison between OTECAC and standalone OTEC systems was also conducted. The results show that: the optimal expansion pressure ratio exists in the power generation system when the isentropic efficiency of the corresponding expander reaches a peak of 21.83% ; lowering the deep sea water temperature and increasing the chilled water flow rate can significantly improve the performance of the OTECAC system, and when the deep sea water temperature is lowered from 9 °C to 4 °C, the integrated exergy efficiency of the system increases from 47.25% to 51.60%; Under the same operating conditions, the OTECAC system has a power generation capacity of 97 W and a cooling capacity of 5 386 W.The thermal efficiency of the system increases from 1.21% to 17.60% after conversion compared to the standalone OTEC system.