The invention discloses a polyamide, glass fiber and interface bonding agent composite and a preparation method thereof. The composite is mainly formed by compositing polyamide, glass fibers and an interface bonding agent, the interface bonding agent is formed by taking polycaprolactam oligomer as a diffusion chain and a silane coupling agent as a binding group through a reaction initiated by initiator, and the composite is prepared from, by weight, 56-90 parts of the polyamide, 5-35 parts of the glass fibers, 1-5 parts of the interface bonding agent, 0.1-1 part of antioxidant and 0.1-3 parts of heat stabilizer. The preparation method comprises the steps of firstly, drying the polyamide and the glass fibers, mixing the interface bonding agent, the antioxidant, the heat stabilizer and the polyamide, adding the glass fibers through a fiber adding opening, adding a mixture through a main material opening, then conducting extrusion and granulation, and conducting drying, so that the composite is obtained. According to the polyamide, glass fiber and interface bonding agent composite and the preparation method thereof, by adding the interface bonding agent, the processing property of a system is improved, the interface bonding situation between a polyamide phase and a glass fiber phase is improved, and meanwhile performance of the composite system is improved.