Aim To study lipoprotein lipase (LPL) gene espression in vitro and observe the mouse LPL activity in post-heparin plasma and various tissue samples we adopted a standard method using radioactive emultion as substrate. Methods 3H-labeled triolein emulsion was prepared and used for subsequent incubation with different enzyme sources. Results There was high LPL activity expression in cultured 293A cells infected with recombinant adenovirus encoding human LPL. The LPL activity of post-heparin plasma,cardiac muscle,and adipose tissue of mice were 314.3 U/L, 349 mU/g and 61 mU/g respectively. Conclusions The method of determination for LPL activity was sensitive,accurate and stable. The results of LPL activity of post-heparin plasma and various tissue samples of mice provided helpful data for further research.