Recently solid state hybrid organometal halide perovskite solar cells have become the research hotspot. We fabricated perovskite solar cells by a simple two-step method completely in the regular ambient condition without a glove box, and all materials were just stored in ambient air. The cross-section SEM image of the perovskite solar cells exhibits a well-defined layer-by-layer structure with clear interfaces. XRD pattern shows main diffraction peaks centred at 14.2° (110) and 28.5° (220), which can be assigned to the CH3NH3PbI3 phase, suggesting a crystal structure, and the peak centred at 12.7° is attributed to PbI2. Our best Jsc is 19.2 mA/cm2, the best Voc is 1.0 V, the best FF is 0.65, and the best PCE is 10.2%.