In order to realize 894.6 nm single mode laser output with low threshold, high stability, we design vertical cavity surface emitting laser (VCSEL) devices with different mesa etching structure and study the influences of mesa diameter, oxide aperture shape and size on lasing performance. The research results show that the larger of the mesa in VCSEL device, the higher the threshold current; the more circular the oxide aperture, the higher the single mode suppression ratio. VCSEL devices with diameter of 4.4 μm circular oxide aperture is achieved, and the device can realize 894.6 nm single mode laser output with driving current of 0.6 mA and working temperature of 70-90 ℃, and the side mode suppression ratio is higher than 35 dB.