The present study evaluated whether EGCG effectively attenuates tumor growth in colon cancer cells and in the xenografts of nude mice and to investigated the underlying mechanisms by focusing on the Shh and PI3K pathways. Three kinds of colon cancer cells and BALB/c nude mice were used to evaluate the antiproliferative effect of EGCG.The results showed that EGCG exhibited an antiproliferative effect against colon cancer cells in a dose-dependent manner with low toxicity against normal colon epithelial cells. Administration of EGCG caused significant apoptosis and inhibited the migration and invasion of colon cancer cells. The toxic effect of EGCG was accompanied by downregulation of the Shh and PI3K/Akt pathways. In addition, EGCG reduced tumor weight without affecting the body weight of nude mice and inhibited the activation of the Shh and PI3K/Akt pathways in tumor tissue. Purmorphamine (Shh agonist) or IGF-1 (PI3K agonist) partly abolished the effect of EGCG on cell proliferation, migration and apoptosis. Cyclopamine (Shh inhibitor) and LY294002 (PI3K inhibitor) showed the similar toxic effects as EGCG on colon cancer cells. In conclusion, EGCG inhibited colon tumor growth via downregulation of the Shh and PI3K pathways and may be a potential chemotherapeutic agent against colon cancer.