Organometal halide perovskites have recently emerged with a huge potential for photovoltaic applications. Moreover, preparation of high-quality perovskite crystals with controlled morphology is of great significance for the fundamental studies such as optical and electrical properties, as well as the applications. Here, we report a one-pot solvothermal process to synthesize sheet-shaped CH3NH3PbBr3 single crystals with the lateral size of 100 µm and the thickness of 3–8 µm. Furthermore, a controlled etching behavior on the crystalline surface was demonstrated, which could be the irregular collapse of the crystalline surface caused by the local accumulation of methylammonium cations. Using this technique, CH3NH3PbBr3 single crystal sheets could be used in the various optoelectronic devices, such as nanolaser, optical sensors, photodetectors and field effect transistors.