Abstract: Taking the liquid desiccant fresh air system driven by heat pump as object of study, the energy balance equations of air loop, concentrated solution loop, refrigerant loop, dilute solution loop and exhaust air loop are established and an energy flow analysis model is determined. According to the test data of typical working condition of the liquid desiccant fresh air system in summer and winter, the energy flow of each loop is mainly discussed. Meanwhile, three different types of energy flow in the liquid desiccant fresh air system were analyzed. The results show that in summer the cold and heat cancel out cold capacity of 1.80 kW between liquid desiccant solution tank and regeneration solution tank, which accounts for about 24.6% of the total cold capacity of the liquid desiccant system, and in winter the cold and heat cancel out cold capacity of 2.00 kW, which accounts for about 29.0% of the total heat capacity of the system. The excess heat generated by the compressor can be balanced by a series auxiliary condenser, the water supply of system is reduced, and the continuous normal operation of the liquid desiccant fresh air system can be ensured.