Abstract: Combined with the market situation of mixed C₅ hydrocarbons in China, using C₅ raw materials produced 1,4- butanediol to avoid that a maleic anhydride method for producing 1,4-butanediol (100000 t/a) was greatly affected by raw materials. The sensitivity analysis of reaction parameters of of n-pentane oxidation to maleic anhydride on the output of phthalic anhydride and maleic anhydride was analyzed by Aspen Plus software, and its optimal operating parameters were determined. Also, the conversion of n-pentane and the yield of phthalic anhydride and maleic anhydride are greatly improved. The simulation results showed the conversion of n-pentane and the yield of phthalic anhydride and maleic anhydride were greatly improved. Under the condition of the same unit consumption, The yield and selectivity of maleic anhydride increased from 34.1% and 6.9% to 45.1% and 32.1% respectively. The yield of phthalic anhydride decreased from 15.7 to 13.5%, and the selectivity of phthalic anhydride increased from 3.2 to 9.6%. The yield and selectivity of carbon monoxide decreased from 43.1% and 8.7% to 32.0% and 2.7% respectively.The optimized reaction conditions were conducive to the oxidation of n-pentane to maleic anhydride leading to an increase in the yield and selectivity of maleic anhydride.