Fauna and flora have great diversities of which approximately 14,000 active pharmaceutical compounds have been isolated. Based on anti-cancer agents, however, oceans are the resources which left intact. Sea cucumbers belong to the Class Holothuroidea of marine invertebrates which has an impressive profile of valuable nutrients and unique pharmacological activities. Sea cucumber extract has biological activities including anti-angiogenic, anti-cancer, anti-inflammatory and anti-oxidant. In the present study, the anti-cancer effects of Holothuria Parva which extracted using the solvents with different polarities consist of n-hexane, ethanol and water were examined by MTT assay on the colon cancer cell line (HT29). The anti-cancer effects of these extracts were examined in 24, 48 and 72 hours on colon cancer cell line forIC_50 (in the range of 0.0399-1.127 mg/ml) then the results were reported. Our results showed that the treatment of human colon cancer cell line HT29 by the water-soluble extract of sea cucumber after 72 hours had the most lethal effects on the tumor cells. Nauplii Artemia urmiana was also used to assess the lethality of sea cucumber extract. The results showed that the extracts had mild effect on the lethality of Artemia. Because of the considerable cytotoxic effects of the aqueous extracts on colon cancer cell line, after purification, these compounds of marine species could be used as good candidate for producing anti - colon cancer drugs.