This paper reviewed the recent progress of the origin, migration and proliferation, sex determination, and genomic modification of murine germ cells during its embryonic development. Murine germ cells originate from primordial germ cells at about 7-7.5dpc. Then PGCs migrated into germinal ridge at about 12.5dpc during which Steel/c-kit signal pathway plays important roles and stopped division at 13.5dpc. The sex of germ cells was mainly determined by the soma microenvironment in the gonad. And there are essential genes for sperm formation on the Y chromosome. The de novo methylation of murine germ cells was much later than soma cells and was completed at about 18.5dpc. The X chromosome reactivation of female germ cells was finished at about 14.5-15.5dpc which was independent of sexual differentiation of germinal ridge.