Objective. So far, it has not been established a satisfactorymethod for early diagnosis and studying on ep idem iology for lep rosy, we want to develop a molecular biologicalmethod for solving th is point. Materials and methods. Based on theM. leprae gene coding groEL, 65kD and 16S rRNA, th ree poly-merase chain reactionsw ere developed by using plikaytis', Woods' and Pattyn's p rocedures. It was op ti-mized that the experimental parameters for each PCR, and a comparative study on practivity among three PCR sw as also conducted for practical purpose. Results and conclusion. For detecting infection with M. leprae, all of PCR s established by us were high ly sensitive and specific, but for practicl purpose, thewoods' PCR optimized by us ought to be chosen firstly.