The present invention belongs to the field of porous catalyst materials, and specifically discloses a graphene oxide composite aerogel and a preparation method and application thereof. The preparation method is as follows: mixing graphene oxide powder and water in solid-liquid ratio of 1: 2 to 1: 6 for ultrasonic dispersion; under stirring conditions, adding nanoscale MnO2 powder, performing hydrothermal reaction, after the reaction is stopped, cooling to room temperature, filtering, washing a filter cake with water, and drying; placing an obtained solid material in an alcohol solution for substitution reaction to obtain a graphene oxide composite hydrogel; finally freeze-drying the graphene oxide hydrogel, and then cooling to obtain the graphene oxide composite aerogel. The catalyst preparation method is simple and easy to operate, the graphene oxide composite aerogel is high in stability, and the catalytic ozonation treatment effect of the graphene oxide composite aerogel is good, and an effective method is provided for advanced treatment of papermaking wastewater.