The perovskite La1-xSrxMnO3 was prepared by sol-gel method under ultrasonic assistant with lanthanum nitrate, strontium nitrate and manganese nitrate as raw materials and doped with grapheme. The La1-xSrxMnO3 and Graphene/La1-xSrxMnO3 composites were characterized by XRD, SEM-EDS, DLS. The effects of calcination temperature and pH on the crystal structure were investigated. We also have investigated the effect of graphene modification on properties of materials. The results show that the La1-xSrxMnO3 prepared by the sol-gel method under ultrasonic assistant have good dispersibility, uniform particle size about 210nm. XRD analysis that Graphene doping does not change the La1-xSrxMnO3 metallography. The first charge and discharge results show that: Compared with pre-modification, the discharge capacity of the Li-air battery with the composite modified by graphene as catalyst was improved to 7900mAh/g from 4300mAh/g.