Abstract: Taking energy efficiency and specific moisture evaporation rate(SMER) as indicators, the performance parameter of heat pump drying system was investigated in order to reduce energy consumption of aquatic product drying process. The energy efficiency of opened heat pump drying system was compared with that of the closed heat pump drying system according to drying characteristics of aquatic product and climate characteristics of subtropical region, and the SMER of closed heat pump drying system was analyzed. The results showed the energy efficiency of opened and closed heat pump systems had little difference with the energy efficiency of 2.39 and 2.52 respectively. Both evaporation temperature and condensing temperature had obvious influence on the SMER, and the former influence was more significant than the latter one. In order to improve the SMER and ensure the productivity, the condensing temperature should be dropped while the evaporation temperature should be increased.