Two hundred and four endophytes isolated from Catharanthus roseus, Cephalotaxus hainanensis and Antiaris toxicaria were screened for antitumor activities. The results showed that broth of 19 strains presented cytotoxic activities to at least one of the tested tumor cells, four of them exhibited strong antitumor activity against S180, were above 70%. Studies have shown that broth in the antitumor active substances of strains PA09006 and PA09009, confer a certain to pH value and ultraviolet.