The important biological characteristics of juvenile Lamprotula leai,such as development,behavior,growth and change of shell shape,were observed by light microscopy.The results showed that the average shell length of newly fallen juvenile was 208.5 μm.After development and growth for 75 days at 23.9-32.8℃,it became the larval mussel with the average shell length of 10.12 mm.The relationships among shell length(L),shell height(H) and age(t) were L=0.220 4 e^{0.051 2t}(R²=0.993 5),H=0.227 7 e^{0.041 8t}(R²=0.994 2),and H=0.781 5 L^0.814(R²=0.998 1),respectively.Based on the change of behavioral features,the juvenile development of L.leai can be divided into crawling stage and burying stage.Furthermore,the crawling stage can be divided into juvenile dropping stage,straight back stage and umbo extruding stage through the change of shell shape,which shows dynamic changes during development and growth juvenile L.leai.