Objective: To investigate the effects of retinoid-related orphan receptor γ (RORγ) gene on proliferation and metastasis of human colon cancer cells． Methods: RORγ knockdown cell lines were constructed and the knockdown efficiency was detected by RT-qPCR and Western blot assays ; MTT，colony formation，Transwell and wound healing assays were used to detect cell proliferation and metastasis ; the expression of epithelial-mesenchymal transition (EMT) related proteins was detected by Western blot．The relationship between RORγ gene expression and immune cell infiltration in tumor microenvironment was analyzed using TIMER 2. 0 database. Results : The knockdown of RORγ enhanced the viability (F = 157. 40，P＜0. 01) ，clonogenesis (F = 61. 35，P＜0. 01) ，migration (F = 13. 00，P＜0. 01) ，invasion (F = 21. 26，P＜0. 01) and wound healing ability (F = 877. 2，P＜0. 01) of colon cancer cells，inhibited the expression of E-Cadherin，and promoted the expression of vimentin and N-Cadherin．TIMER 2. 0 database analysis showed that RORγ expression in colon adenocarcinoma ( COAD) tissues was associated with multiple immune cell infiltrates． Conclusion Downregulation of RORγ expression promoted the proliferation and metastasis of colon cancer cells.