Abstract: To explore the effect of different amount of organic manure on the yield of sweet potato, a trial of different amount application of organic manure was carried out by using ‘Guangshu 84’ as the experimental material and 8 different experimental treatments. The results showed that with the increase of fertilizer application, the yield of sweet potato and the rate of large and medium tubers increased, and when the fertilizer amount was 15 000 kg·hm^-2, the yield reached the highest level of 54 225 kg·hm^-2, which increased 67.9% compared with the control and reached a very significant level. When the amount of fertilizer increased further, the yield of sweet potato and the rate of large and medium tubers decreased. Considering the factors of cost, the economic benefit was the best while the application of organic was 11 250 kg·hm^-2.