Objective To study the expression of PIWIL1, PIWIL3 and PIWIL4 in human colon cancer and its clinical significance. Methods We collected cancerous tissues and its adjacent tissues of 106 patients with colon cancer, two tissue microarrays were constructed, with 62 and 150 points respectively. We studied the expression of PIWIL1, PIWIL3 and PIWIL4 through immunohistochemistry. Results The expression of PIWIL1, PIWIL3 and PIWIL4 were significantly higher in cancerous tissues than those in adjacent tissues (P＜0. 01). In cancerous tissues and its adjacent tissues, postive correlation were seen among PIWIL1, PIWIL3 and PIWIL4 expression (P＜0. 01). PIWIL1 expression was significant higher in low differentiation group than that in high differentiation group (t =- 2. 840, P＜0.01 ). PIWIL3 expression was higher in high clinical stage than that in low clinical stage (F= 3. 112, P＜0.05). The expression of PIWIL3 and PIWIL4 were significantly higher in patients with colon cancer with distant metastasis than those without distant metastasis (t= -3. 349, P＜0.01 ; t = - 2. 168, P＜0. 05). PIWIL3 and PIWIL4 expression were correlated with occurring of colon cancer (P＜0. 01). Conclusions The expressions of PIWIL1,PIWIL3 and PIWIL4 in colon cancer were correlated with the differentiation, clinical stage and distant metastasis of colon cancer. PIWIL3 and PIWIL4 expression were two independent related factors of occurring of colon cancer, which would be furtherly investigated to be served as novel markers for early diagnosis and promising molecular targets for colon cancer therapy.