Abstract: In order to explore the comprehensive benefits of different biochar application modes（different biochar application amounts and application years） on sloping farmland in the black soil region, a 3° slope farmland runoff plot in the black soil region of Northeast China was taken as the research object, and experimental research was conducted from 2015 to 2018, the conventional treatment without biochar（C0） was set, and the applied amount of biochar were 25 t/hm~2（C25）, 50 t/hm~2（C50）, 75 t/hm~2（C75）, 100 t/hm~2（C100） to analyze the comprehensive benefits of different amounts of biochar application and the duration of biochar application, the results showed that in terms of ecological benefits, biochar can effectively improve soil structure, enhance soil fertility, and improve soil water storage and soil conservation capacity. For two years of continuous application, the effect of soil water retention and soil conservation was the best when the amount of biochar applied was 50 t/hm~2; for three years of continuous application, the soil structure was optimal when the amount of carbon applied was 50 t/hm~2; for four years of continuous application soil fertility was the best when the amount of carbon was 100 t/hm~2. In terms of economic benefits, biochar can effectively improve crop water-saving, yield-generating performance and its economic output value. Applied for one year, when the amount of biochar was 75 t/hm~2, the water use efficiency reached the maximum. For two consecutive years, when the amount of biochar was 25 t/hm~2, the marginal productivity of biochar was the largest. For each additional ton of biochar applied, the output was increased by 11.20 kg. For three consecutive years of application, when the amount of biochar applied was 50 t/hm~2, the soybean yield was the best; for four years of continuous application, when the amount of biochar applied was 50 t/hm~2, the return reached the maximum value. The improved fuzzy comprehensive evaluation model was used to calculate the ecological benefit, economic benefit and comprehensive benefit of different biochar application models. The results showed that the ecological benefit index reached the maximum value when the biochar application amount was 72.74 t/hm~2 for two consecutive years of application, the economic benefit index reached the maximum value when the biochar application amount was 36.32 t/hm~2 for three consecutive years of application. The best biochar application mode in the black soil area was continuous application for three years, and the biochar application amount was 62.30 t/hm~2.