In this study, the impedance controlling effects of deep loosening building block on losses of different forms of phosphorus (P) on black soil sloping farmland were studied. The results show that: Deep loosening building block could Intercept runoff and sediment, and reduce soil and water loss on sloping farmland. Compared with CK, deep loosening building block processing reduced the total P concentration, dissolvable total P concentration, and particulate P concentration in farmland runoff by 58.19%, 64.19% and 55.02%, respectively; it could reduce the cumulative loss of total P concentration, dissolvable total P concentration, and particulate P concentration by up to 89.32%, 90.74% and 88.48%, respectively. Relatively speaking, the effects of deep loosening building block on reducing dissolvable total P concentration in runoff was better, particulate P was the predominant form of phosphorus lost in the runoff of black soil sloping farmland. Deep loosening building block measures had certain controlling effects on reducing the losses of different form of phosphorus in the runoff of sloping farmland.