Abstract: Objective 　To investigate the expression CD105 in newborn vessel of COX-2 and VEGF in colorectal carcinoma and their relationship with angiogenesis. Methods 　Immunohisto-chemical staining (S-P method) for CD105, COX-2 and VEGF was performed in 58 cases of colorectal carcinoma ; the microvessel density (MVD) was marked by CD105. Results 　The value of MVD with marked CD105 was (36. 50 ±9. 59), the positive rate of COX-2 and VEGF were respectively 69 % and 67. 2 %. The MVD in COX-2 positive group or VEGF positive group was significantly higher than that in COX-2 negative group or VEGF negative group ( P < 0. 01) . The MVD in the group of both COX-2 and VEGF positive was significantly higher than that in both negative groups. There was a significant positive correlation between the expression of COX-2 and VEGF. Conclusion 　CD105 was a specific marker of newborn vessel in colorectal carcinoma ; COX-2 was correlated to angiogenesis and VEGF may be an important mediator in this process.