Due to its powerful regeneration capability, planarian has become the model organism of developmental biology and regenerative biology. Furthermore, planarian also shows unique reproductive characteristics and draws more and more attention. Recently, researches on planarian reproductive biology are mainly focusing on two aspects: 1. mechanism of asexual to sexual reproduction switch; 2. cloning, expression and function analysis of reproduction-related genes. As for the mechanism of reproduction switch, works mainly include the discovery of sexualization of planarian, the seasonal change of sexualization, the downstream events after sexualization, and the exploration of sex-inducing substance. Till now, the reproduction-related genes DjPTK1, vasa-like genes (DjvlgA/DjvlgB), DeY1, Dryg, nanos-related genes (Djnos/Smednos/Dr-nanos) and Drpiwi-1 have been cloned, and their expression patterns and functions have been explored. Furthermore, the problem and future tendency in planarian reproductive biology have also been summarized.