A large size (about 150 μm) high quality MAPbI3 single crystals have been grown by modifying the surface of the substrate to control the nucleation position. Furthermore, the growth factors of PbI2 crystals was studied systematically, mainly including substrate temperature, flow rate of carrier gas, time effect. The results showed that the best conditions for the crystal growth correspond to 350 ℃, 20 sccm and 20 min. In addition, the perovskite single crystalline was measured by XRD when exposed to air for 50 days or more. Although the characteristic peaks were different in size, the crystal did not change as a whole. By analyzing the optoelectronic properties of device, we found that the switch ratio of device is up to 104, and its responsivity is 3.8×104 A/W. In addition, the device shows a fast response (rise time: 0.03 s; fall time: 0.15 s). The above shows that our developed MAPbI3 single crystal photodetector will have a very good application in the field of optoelectronics.