The invention provides a high heat resistance and low warping nylon 66 composite and a preparation method thereof. The nylon 66 composite is characterized in that the composite comprises the following raw materials in parts by weight: 41.9-79.6 parts of nylon resin, 10-30 parts of chopped glass fiber, 10-25 parts of mineral filler, 0.1-0.9 parts of surface conditioning agent, 0.1-0.6 parts of nucleator, 0.1-0.6 parts of heat stabilizer, and 0.1-1 part of lubricant, wherein the nylon resin is nylon 66 of which the relative viscosity [eta] is 2.4-3.2 (Ubbelohde viscosimetry). According to the high heat resistance and low warping nylon 66 composite, the glass fiber and mineral powder are composited and filled, and aids such as the heat stabilizer, the nucleator and the lubricant are added. The glass fiber and the mineral powder subjected to surface treatment have a good interface bonding property with the nylon 66 resin. The prepared nylon composite has excellent dimensional stability, good mechanical property, and excellent long-term thermo-oxidative aging resistance, and can be widely applied to the fields of peripheral parts of an automobile engine, electric products and the like.