The dimethyl sulfoxide (DMSO) solvent treatment is introduced into the perovskite polymer solar cell to improve its properties. The X-ray diffraction (XRD) has been used to analyze the remnant PbI2 in the film after the reaction and the morphologies of the perovskite and PbI2 films are investigated by using a scanning electron microscope (SEM). Current-Voltage (I-V), absorption and external quantum efficiency (EQE) measurements are carried out to investigate the differences of the properties between the devices with and without the solvent treatment. Through investigation, a significant improvement is found in short circuit current (Jsc) of the devices treated by DMSO and the efficiency achieved 11.1%, which has improved 17.2% when compared with the devices without solvent treatment. This method will reduce the remnant of PbI2 and change the crystal size as well as surface morphology of perovskite film, which results in an enhanced property.