The invention discloses a Janus particle/epoxy resin composite material which is prepared by the following steps: adding mixed powder of polystyrene and polydivinylbenzene into deionized water, then adding aluminum oxide, conducting ultrasonic dispersing, then adding azodiisobutyronitrile, conducting ultrasonic stirring, then adding a formed solution into a sodium dodecyl benzene sulfonate aqueoussolution, conducting ultrasonic dispersing, adding gamma-methacryloyloxypropyltrimethoxysilane into epoxy resin, dropwise adding an alkaline substance to adjust the pH value to 9, conducting heatingfor reaction, conducting cooling and centrifuging, conducting washing with an absolute ethyl alcohol solution for three times to obtain Janus microsphere particles, adding the Janus microsphere particles into epoxy resin, adding a curing agent, conducting heating and stirring, pouring a formed mixture into a preheated mold, conducting curing for a period of time, and conducting cooling to obtain the Janus particle/epoxy resin composite material. The Janus particle/epoxy resin composite material effectively prevents crack development on an interface, so that the mechanical property of the prepared composite material is improved.