In view of the inaccuracy of artificial fertilizer application amount and uneven fertilization of orchard organic fertilizer, an organic fertilizer strip spreading rotary tillage mixed fertilizer application machine was designed according to the requirements of fertilization agronomic. The device used scraper drainage fertilizer, through the ring chain to drive the scraper to the front row of fertilizer, and spread organic manure in strips on the surface, then the rotary tillage device would be mixed with the soil. First of all, through the design calculation, the maximum opening height of the fertilizer device, fertilizer box volume and other structural parameters were determined, and the upper and lower organic fertilizer discharge process was analyzed. Then, discrete element simulation test was carried out with the opening height of fertilizer discharge port, forward speed, sprocket speed and scraper spacing as test factors. The parameters were solved with the relative error and variation coefficient of organic fertilizer as evaluation indexes, and the working parameters of fertilizer discharge process were optimized and solved. The optimal parameter combination was obtained as follows: the opening height was 53.17mm, the forward speed was 2.8km/h, the sprocket speed was 15.96r/min, and the scraper spacing was 160mm. The experimental verification under the optimal working conditions showed that the average organic fertilizer discharge was 5.099kg/m2, the relative error was 4.5% and the coefficient of variation was 8.8%. This showed that the simulation optimization results were reliable, the fertilizer discharge was accurate and the uniformity of fertilizer discharge was good, and the fertilization performance of the fertilization device was good. Finally, in the rotary tillage mixing test, the mixing ratio of upper organic fertilizer was 11.83%, and that of lower organic fertilizer was 6.29%, indicating that after rotary tillage, soil and fertilizer mixing effect could be achieved, and the mixing ratio of upper soil and fertilizer was higher than that of the lower layer.