The effect of three planting density on economic output of seed-used pumpkin ‘Yinhui No.2’ was studied in the year 2010~2011.The results showed that the seed yield were significantly influenced by planting density.When planting density was too large，the seedling was excessive growth，petioles was crisp and easily broken；powdery mildew of pumpkin was aggravated，the rate of rotten fruit would increase and fruit-bearing exponential was decline. 15 000 plants/hm2 was the suitable planting density，in this density the output value was maximum and cost-benefit was the highest.