Abstract: A kind of high linearity piezoresistive micromachining accelerometer with low range is reported on its mechanism, structure, fabrication processing and performance test. To improve its sensitivity, this sensor adopt cantilever beam-island structure. After theoretical calculation, it can be concluded that because the center of mass isn't in central plane, inertial force will produce bending stress in piezoresistance, that is the main source of transverse sensitivity. And for the sensor frequency character, damping factor can be modifed by changing air gap between cover board and sensing element.