Abstract: The activities of acid - and alkaline - phosphatase (ACP and AKP) in rat liver cells under normal and heat shock conditions were examined. The results showed that the best incubation time that enzymes interacting substrates is 40 min and 2.5h respectively. The rats were treated by heat shock at 42、44 and 46℃ respectively for 30min,then maintained at 25℃ for 24h，it was found that the activities of ACP and AKP in rat liver cells were the most active at 42℃ for 30 min. By heat shock of 46℃ for 30min ,and then at 25℃ for 1 -120h，ACP and AKP were the most active at 48h. The significance of ACP and AKP activi-tives responed to heat shock by rats was discussed.

Key words: "Hepatocytes, Heat shock, Acid phosphatase, Alkaline, phosphatase, Rat "