【Objective】To study the expression of Tip60（KAT5）in Oral squamous cell carcinoma（OSCC），and to investigate the relationship of Tip60（KAT5）and OSCC.【Methods】Forty-nine samples of OSCC and 36 samples of nor⁃ mal tissue adjacent to OSCC were collected and analyzed retrospectively. The expression of Tip60（KAT5）was detected by immunehisto chemistry using Envision detection system. OSCC cell line Cal27 and UM1 cultured in vitro were treated with Nu9056，an inhibitor of Tip60（KAT5）for 24h，respectively. Then the effect of different concentrations and times on the growth of Cal27 and UM1 cells was evaluated with MTT assay.【Results】The expression of Tip60（KAT5）in OSCC was significantly higher than that in normal tissue adjacent to OSCC（P=0.000）. Its expression was significantly positively correlated with the degree of histological differentiation（r=0.461，P=0.001）. With the increase of concentration，the proliferation inhibition rate of Nu9056 on Cal27 and UM1 cells gradually increased，showing a concentration- dependent and time-dependent relationship（P<0.05）.【Conclusions】The expression of Tip60（KAT5）protein in oral squamous cell carcinoma tissues was related to the degree of histological differentiation ，Tip60（KAT5）can be used as oral squamous cell carcinoma progression and prognosis of biological indicators.