In the design and fabrication of microelectronic system(MEMS)devices, the process based on silicon is a main technolog which draws great attention of researchers. Bonding technology including silicon to glass and silicon to silicon is fundamental for bulk silicon MEMS devices.For MEMS devices, the bonding area is from the micrometer to millimeter scale, thus traditional methods to test bonding strength are no longer feasible. Measuring the strength at that scale has become the bottle-neck for MEMS development. We first define a new way, with which a series of single crystal cantilever beam was taken to test the maxal shear stress of bonding strength in the micro area.The experiment gives curves of torsional strength versus the bonding area and torsional strength versus the probe movement distance, the designer can use them to determine the bonding area according to the required torque for their MEMS devices.