Micro-cantilever is key component of a new type of force sensor and its property determines the accuracy of the result of mechanical test.Micro-cantilever should be calibrated with the purpose of obtaining the mechanical properties in quantity.A new calibration method of the lateral coefficient of elasticity is presented.By using an ultra precision balance and the optical lever respectively

the lateral force and the torsional deflection are measured.The lateral coefficient of elasticity is then simply obtained.The lateral coefficient of elasticity of three types of cantilevers are calibrated and the standard mean square deviations are less than 5%

which shows good repeatability.The experimental result is in agreement with the finite element analysis result.