Abstract: Objective To investigate the expression of BMP-9 （bone morphogenetic protein-9） in colorectal cancer （CRC） and the relationship between BMP-9 and clinicopathological characteristics of CRC. Methods The colorectal adenoma and carcinoma tissues and its corresponding normal colorectal mucosa from 65 patients with a pathologically proven diagnosis of colorectal adenoma and adenocarcinoma from the department of pathology in the First Affiliated Hospital of Liaoning Medical University from May 2012 to October 2014 were examined for BMP-9 and cell proliferative factor Ki-67 expressions using immunohistochemistry. Results The positive rate of BMP-9 expression in the normal colorectal mucosa， adenoma and colorectal carcinoma was 68% （44/65）， 91%（59/65） and 95% （62/65）， respectively. The expression of BMP-9 in colorectal carcinoma tissues was significantly higher than that in adenoma tissues （P＜ 0.05）， and the expression of BMP-9 in adenoma tissues was higher than that in normal mucosa （P＜ 0.05）. However， there was no correlation between expression of BMP-9 and tumor location and types， degree of differentiation， histological type， WHO histological classification， vessel cancer embolus， TNM stage and the level of tumor marker CEA and CA19-9 in the serum of CRC （P＞ 0.05）. The expression of BMP-9 was not correlated to the level of cell proliferative factor Ki-67 （P＞ 0.05）. There was no correlation between expression of BMP-9 and clinicopathological characteristics in colorectal adenoma （P＞ 0.05）. Conclusion The increasing level of BMP-9 in normal colorectal mucosa- adenoma- carcinoma tissues indicates that BMP-9 may promote the development and progression of colorectal carcinoma.