A new segmented tip-tilt deformable mirror (DM) based on surface micromachining process is proposed, a mirror array with 3×4 elements is fabricated. In this new structure every mirror suface has one only actuator so that the mirror array has a continuous surface topography, and the residual stress in the fabrication process can be effectively released with a result that the curl of the surface is reduced. The resonance frequency and the relationship between displacement and voltage are calculated based on the theory of elasticity and simulated based on a finite elements analysis (FEA) software. Then the fabricated device is tested by an optical profiler. Experimental results indicate that the actuated array has a piston-tip-tilt (PTT) motion, and the mirror has a stroke of approximately 0.76 μm under 3.75 V driving voltage, which is coincident with the theoretical analysis. Compared with previous reported segmented tip-tilt DM, this new structure has a lower working voltage and a fewer amount of actuators, and provides a possibility of integrating a large-actuator-count DM with integrated circuit (IC) on one chip.