The invention discloses an air fog quenching production line capable of obtaining variable-strength car structural parts and a production technology thereof. The production line comprises a high-strength steel uncoiling device, a high-strength steel tailoring device, a first conveying device, a cold stamping device, a second conveying device, a heating device, a third conveying device, an air fog quenching device and a fourth conveying device which are sequentially arranged along the straight line; the air fog quenching device comprises a top frame and a bottom frame; the top frame comprises a first sprayer set, a second sprayer set and corresponding drive devices; an air compressor, a high-pressure gas storage bottle, a water storage tank, a high-pressure air pipe, a high-pressure water pipe, a waste water draining pipe and a waste water treatment system are arranged in the bottom frame, and a fifth conveying device is arranged at the upper end of the bottom frame. The production line has the beneficial effects of being high in automation degree, high in integration degree, high in production efficiency, low in production cost, good in work environment and the like. Manufacturing of heat-treatable reinforcement high-strength steel parts with the mechanical property gradient distribution is achieved, and car body safety and lightweight targets can be effectively achieved.