A MEMS device for in-situ TEM/AFM/SEM/STM testing of nano structures is designed. Two deformation measurement methods are discussed: microscopic measurement and electrical measurement. For the first method, the device consists of a comb-drive actuator, calibration beam and specimen stage. The stiffness of the specimen can be well characterized by comparing the load-displacement relation before and after the attachment of the specimen. For the second method, the device is composed of a comb-drive actuator, specimen stage and a beam-type load sensor. The load and displacement of the specimen are measured independently. Deformation fields will be obtained by means of a full field technique, with natural or artificial nano patterns to be correlated, while the load sensor identifies the load applied to the specimen by measuring voltage changes. This device demonstrates the feasibility of ultra-high resolution mechanical property measurements in small systems by means of MEMS techniques. The subsequent experiments are expected to identify the mechanical properties such as fracture, fatigue, and inelastic deformation mechanisms of nano structures, by quantifying defect sources, their kinetics, and interactions.