The invention discloses a temperature-resistant type emulsion sizing agent for a carbon fiber. The temperature-resistant type emulsion sizing agent comprises the following materials: main size, an emulsifying agent, an additive and deionized water, wherein the main size is glycidyl amine type epoxy resin modified by dodecanamine, and in modification, the mass ratio of dodecanamine to the epoxy resin is (10-40) to (60-90); the mass of the emulsifying agent is 5-15% of the mass of the main size; the additive comprises a diluting agent and a penetrating agent, the mass of the diluting agent is 0-100% of the mass of the main size, and the mass of the penetrating agent is 1-5% of the mass of the main size; the mass ratio of the deionized water to the main size is (50-90) to (10-50). The invention also discloses a preparation method and application of the sizing agent. The sizing agent disclosed by the invention is high in stability and does not cause pollution to the environment, and the preparation method is simple; in the presence of a flexible molecule, namely dodecanamine, the carbon fiber has relatively high operability; proved by experiments, after the carbon fiber is treated by the sizing agent, the post processability is obviously improved; and the interface temperature resistance and the interlaminar shear strength (ILSS) of the carbon-fiber-enhanced epoxy resin composite material are also obviously improved.