The invention relates to a high-thermal-conductivity insulating polyamide composite material and a preparation method thereof. The high-thermal-conductivity insulating polyamide composite material is prepared from the following raw materials: polyamide 10T/11 resin, aliphatic polyamide resin, toluene diisocynate, 2,2'-(1,3-phenylene)-bisoxazoline, a coupling reagent, boron nitride, aluminum oxide, silicon carbide, N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,3-phthalic diamide and bis(2,6-ditert-butyl-4-methylphenyl) pentaerythritol diphosphate. The high-thermal-conductivity insulating polyamide composite material has the characteristics of high heat conductivity coefficient, high tensile strength, high fluidity, low water absorption rate and good insulating property, can be applied to the field of the electronic and electric industry, the LED industry and the automobile industry.