To improve the water use efficiency in dry farming areas at the northern foothill of Yinshan mountain in Inner Mongolia，the effects of four different tillage methods，namely，biochar and organic manure combined(BM)，biochar alone(B)，organic manure alone(M)and no biochar and organic manure(CK)，on the temporal and spatial changes of soil moisture，soil water consumption characteristics，and agronomic traits，yield components and water use efficiency in key growth stages of oats were compared and analyzed.The results showed that biochar，organic manure and their combination promoted the growth and development of oats.Compared with CK，the plant height of B，M and BM oats increased by 17.73%，22.29% and 26.03%，respectively，the leaf area per plant increased by 13.32%，17.05% and 23.67%，and the aboveground dry matter increased by 6.48%，7.39% and 20.30%，respectively.The effect of biochar was better than that of organic manure in the early and middle stages of oat growth，and the effect of organic manure was better than that of biochar in the late growth，and the coupling effect was the best.BM increased soil water content of 0～40 cm by 1.65%～19.12%，significantly reduced oat soil water storage consumption by 11.34%～20.09%，and total water consumption by 0.38%～0.88%.The effect of biochar on water conservation and consumption reduction was stronger than that of organic manure.With the growth period and precipitation increasing，the difference between the two effects decreased gradually.In terms of yield，BM simultaneously significantly increased the number of harvested spikes，grain number per spike and grain weight per spike，and promoted the formation of grain yield and water use efficiency of oats.Grain yield increased by 7.63%～14.80%，and water use efficiency increases by 8.62%～16.64%.Combined application of biochar and organic manure can significantly promote the growth of dryland oats，effectively maintain soil moisture，and improve water use efficiency and yield of oats.It is a drought-resistant and moisture-conserving technical measure suitable for dryland oat planting in the northern foothill of Yinshan mountain in Inner Mongolia.