Clarifying the characteristics of runoff and sediment yield in vacant farmlands on slopes can shed some light on the comprehensive management of water and soil resources of sloping farmlands. Taking the red soil developed from Quaternary red clay as the research object, the characteristics of runoff and sediment yield of a plot of vacant sloping farmland under natural rainfall conditions and the response mechanism to rainfall characteristics were analyzed by long term field runoff plot positioning test. The results show that the soil erosion of the vacant sloping farmland was above the high erosion level, and the runoff and sediment yield decreased insignificantly year by year, which was negatively related to the duration of annual rainfall. The runoff and sediment yield were mainly concentrated to the period of April-September, accounting for 96.73% and 99.35% of the total annual amount, respectively. There was almost no runoff and sediment yield in small rainfall type, whereas the rainstorm type and above contributed largely to the runoff and sediment yield, with the contribution rate all exceeding 80 %. The driving model of rainfall, rainfall duration, rainfall kinetic energy and rainfall erosivity on runoff yield showed quadratic function relationship, and the driving model of maximum 30 minute rainfall intensity was power function relationship. The driving models of rainfall kinetic energy, rainfall erosivity and maximum 30 minute rainfall intensity on sediment yield showed power function relationship, whereas the driving models of rainfall and rainfall duration was linear function and quadratic function relationship, respectively. The determinable coefficients of runoff driving models were all greater than those of sediment driving models, and the runoff and sediment yield showed power function relationship.