According to the evaluating standards of two-stroke gasoline engine oil's lubricity published by ISO and Sinopec, the lubricity of two-stroke lubricant’s base oils that mainly constituted by trimethylol propane ester (TMP) has been investigated. The research results indicated that TMP had excellent high-temperature lubricity under the engine operating conditions. The lubricity was better when using higher high-temperature viscosity TMP. The mixed ester had better lubricity than any single composition in the mixture. But the effect of anti-wear additives on lubricity in ester base oils could not be investigated by the evaluating method of lubricity.