The invention relates to an epoxy-organic silicon polyimide adhesive comprising the following components: organic silicon polyimide (SPI) resin, multifunctional epoxy resin, a curing agent, an accelerating agent and an organic solvent. The preparation method of the epoxy-organic silicon polyimide adhesive comprises the following steps of: adding the SPI resin to a reactor for reacting for 0.5 hours at 130 DEG C, then cooling, adding the organic solvent, and stirring for dissolution to obtain a component A; stirring the curing agent, the accelerating agent and the organic solvent for dissolution to obtain a component solution B; and when in use, uniformly mixing and stirring the components A, B to obtain the epoxy-organic silicon polyimide adhesive. The tensile sheering strength of the epoxy-organic silicon polyimide adhesive reaches 25.4 MPa at the room temperature, and the epoxy-organic silicon polyimide adhesive also has the advantages of excellent heat resistance, strong hydrophobicity, simple preparation process and low cost, is beneficial to realizing industrial production and has extensive application prospects in the fields of electronics, microelectronics, flexible copper--clad laminates, flexible printed circuit boards, hard copper-clad laminates, motors, aerospace and the like.