The invention relates to the field of porous foamed materials, and concretely relates to a preparation method of an open-celled organic foamed material. The preparation method of the open-celled organic foamed material comprises the following steps: respectively adding a surfactant, an initiator and a foaming agent into a monomer, and uniformly stirring above substances to obtain an oil phase solution; dropwise adding water to the oil phase solution under a stirring condition, and continuously stirring the water and the oil phase solution to obtain a concentrated emulsion; pouring the concentrated emulsion into a die, carrying out a polymerization reaction at 50-90 DEG C, drying the obtained reaction product at 60-90 DEG C to volatilize the obtained water phase form holes in order to obtain an open-celled organic foamed base material; and carrying out secondary foaming treatment on the open-celled organic foamed base material at 93-300 DEG C to obtain the open-celled organic foamed material. The open-celled organic foamed material has the advantages of high perforation ratio, many through holes, high BET specific surface area, and realization of the change of the hole diameter through changing the addition amounts of the foaming agent and a foaming inducing agent.