Abstract Here, we demonstrate a facile strategy to enhance the efficiency and stability of perovskite solar cells (PKSCs) by modification the perovskite with a simple small molecule SnPc layer. A maximum PCE of 16.52% has been achieved in the modified PKSCs and it increases by 25% in compared with the pristine device (13.2%). The improvement of photovoltaic performance should be ascribed to the enhancement of holes transport and the reduction of charge recombination by SnPc modification. Moreover, the stability of PKSCs has also been improved remarkably due to the protection of the hydrophobic SnPc layer, and the device can keep over 86% initial PCE even after exposure for 90 days under ambient environment (25 °C relative humidity RH = 30%) without encapsulation.