The movement status of the deivce needs to be determined accurately under the driven conditions in the design and fabrication of the optoelectronic devices based on the micro-opto-electro-mechanical systems (MOEMS). Because of the limitation of geometrical dimensions, there are some difficulties in accurate measurement on the driven conditions for MOEMS optical switch. This paper presents an optical method for the measurement of the angular rotation of the cantilever beam on the optical switch. Based on the theoretical analysis, the relations of the angular rotation and the measurable parameters are given, and the optimized results of the measurable parameters are performed. The measure error is less 10% and the experimental results obtained demonstrate that the feasibility of the proposed method to be used for evaluating the driven conditions of the MOEMS optical switch.