Objective: To investigate the expression of tumor-associated antigen OYA66 in human tumor tissues, and explore its clinical values. Methods: Immunohistochemistry was employed to detect the expression of OYA66 protein in several types of tumor tissue chips and samples (gastric cancer, intestinal cancer, lung cancer, breast cancer, ovarian cancer, bladder cancer and renal cancer) and corresponding non-tumor tissues. The relationship between the expression of 0VA66 protein and character of tumor tissues, tumor metastasis and clinicopathological characteristics was analysed. Results: There was high expression of OYA66 protein in the tumor tissues of stomach, intestine, ovary, 1 (ladder and kidney, which was significantly higher than that in non-tumor tissues. While the expression of OVA66 was relatively lower in the tumor tissues of lung and breast. The expression of OVA66 in bladder cancer tissues was related to the pathological grading of bladder cancer. The expression of 0VA66 in intestinal cancer and bladder cancer with lymph node metastasis was slightly higher than that in intestinal cancer and bladder cancer without lymph node metastasis, while there was no significant difference between them. Conclusion: There is high expression of OVA66 protein in many tumor tissues. The expression of 0VA66 protein in bladder cancer tissues is related to the pathological grading of bladder cancer. 0VA66 may serve as a novel tumor marker in the diagnosis of tumors.