Aiming at the stiffness measurement requirements of elastic elements with high accuracy and small deformation, and taking the elastic test of tapered elastic washers in GB/T 94.4 as an example to analyze the problems existing in the domestic universal stiffness measuring instrument when measuring elastic elements with high accuracy and small deformed. Through analysis and experimental verification, and discuss the selection of the displacement measuring device, it is concluded that when designing the stiffness measuring instrument with high accuracy, the cantilever beam loading mechanism and the cantilever beam load measuring device should be avoided. It is proposed a stiffness measuring instrument with high accuracy design scheme that the load measuring device adopts the column force sensor and the displacement measuring device adopts the laser displacement sensor, and the force applying mechanism adopts a double column type .