To　explore　the　antineoplastic　effect　in　vitro　of　earthworm　coelomic　fluid　(ECF)on　growth　inhibition　and　its　mechanism　for　the　tumor　cell　lines　Siha,　SW480,　Colo205　and　PC12.　MTT　colorimetric　assay,　flow　cytometry　and　morphological　analysis　were　used　to　test　its　antitumor　activity　on　tumor　cell　lines　and　normal　cell　line　Cos7　in　vitro.　ECF　can　inhibit　the　cell　growth　of　Siha,　SW480,　Colo205,　PC12　and　Cos7.　But　different　tumor　cell　lines　showed　different　sensitivity.　EFC　can　significantly　inhibit　the　proliferation　of　tumor　cells　in　vitro　by　inducing　tumor　cells　apoptosis.