Abstract: A new approach based on machine vision to measure the force during microassembly was proposed. After the acquisition of outoffocus blur image of microgripper under force, with the established model of the relationship between the force and the outoffocus blur parameter, the problem of force measurement is transformed into that of blur parameter identification. A coarsefine blur identification method is then put forwarded, where microgripper’s bending curve is used for curve fitting the blur parameters. The coefficient of the fitted curve has a direct relationship with the force. The simulation results show this method’s validity.