Abstract: KOH silicon maskless anisotropic etching technology is adopted to fabricate a symmetric beam-mass structure accelerometer. Lateral sensitivity effect in conventional accelerometers is eliminated because the beams are located symmetrically to the middle of the seismic mass. Based on the calculation of sensitivity and basic resonant frequency of two kinds of bulk micromachining accelerometers, the structure parameters of cantilever and double-side-supported accelerometer have been optimized by using the sensitivity-frequency product as the figure of merit of the structures. The different etching characteristics of 311 and 100 plane of silicon in KOH maskless anisotropic etching process have been utilized in the fabrication of the symmetric beam-mass structure. Preliminary measurement of the static characteristics of the structure has been performed with a force-deflection balance measurement apparatus.