The invention provides a processing method of sumac seedling seeds. The method comprises the steps of storing sumac seeds in sand, soaking the seeds in saline solution, and cleaning; soaking the seeds in washing powder water, rubbing the surfaces of the seeds to remove wax, and putting the seeds into a woven bag; spraying warm water onto the seeds every other 2 hours until the seeds are expanded and the seed coats are softened; putting the seeds into a breathable bamboo frame or a plastic frame, and watering until the seeds crack and sprout. According to the processing method, the characteristics that the sumac seedling seeds have after-ripening embryo, and seed shells are firm, seed coats are compact and the waxiness is thick can be effectively broken, the cultivation of the high-quality sumac nursery stock can be facilitated, the germination rate of the sumac seeds reaches more than 50% after 5-6 days, the sumac seeds can be planted in the nursery garden land by broadcast sowing or hill-seeding in the seventh day, the germination rate reaches up to more than 95% within 15 days after sowing, and 60% of seeds can germinate within a week. According to the processing method, the germination period is short, more than half time can be shortened, the seeds can be processed in batches on a large scale, and the cost is low; furthermore, a chemical reagent with high harmfulness is eliminated, and the processing method has the characteristics of being safe, environmentally friendly and easy to operate.