Subsidy efficiency is the core standard to test the rationality of subsidy system design and the effectiveness of its operation. It is found that there are problems of efficiency loss and welfare erosion in China"s general aviation service industry subsidy system, such as relative supply squeeze, temporary income trap, vicious loss operation and internal circulation of funds. Subsidies have no significant effect on business efficiency of general aviation companies. Based on the damaged form of subsidy efficiency and conforming to the contradiction between effective supply and demand, taking social welfare and externality as the core, starting from the two dimensions of structural remodeling and mechanism optimization, this paper comprehensively establishes the subsidy system of China"s general aviation service industry, explores the Optimal Subsidy boundary, and maximizes the subsidy benefits. Firstly, based on the two-dimensional influence mechanism of demand, a two-sided subsidy model of "demand side premium rate subsidy system + supply side flexible Subsidy Plan" is established to slow down the excessive intensification of short-term irrational subsidy behavior caused by the small effective supply and demand scale. Secondly, the supply side subsidy plan is deeply optimized from the following four aspects: adjusting the subsidy standard, enriching the subsidy level, standardizing the subsidy process and positioning the subsidy attribute, and refining the demand side subsidy content in the form of applying post subsidy arrangement and preparing to build reinsurance subsidy fund, so as to minimize the impairment of subsidy efficiency loss on the expected subsidy benefits.