【Objective】Modifying soil physical properties is an important approach to improving soil anti-erodibility. As by-product of some industries, corn stalk sap is often discharged as waste. Recent studies have demonstrated that spraying corn stalk sap in the field may control sheet erosion. However, little is available in literature regarding effects of corn stalk sap controlling splash erosion and wind erosion. 【Method】In this study, a new soil amendment consisting 95%～97% corn stalk sap and 3%～5% preservative (sodium benzoate) was tested in a field subjected to artificial rainfalls, winds and in situ observation to explore its effects of controlling splash, sheet, and wind erosion of loessial soil and their mechanisms. The experiment was designed to have two treatments for ingredient of the spray (corn stalk sap and tap water, the same in spraying volume), two treatments for standing time after spraying (7 and 14 d) and two treatments for soil tillage condition (with and without manual plough). 【Result】Results show that corn stalk sap was quite effective in controlling water and wind erosion of loessial soil. Under simulated rainfalls, it reduced splash erosion by 24.7%～78.3%, runoff by 35.3%～45.3%and sheet erosion by 20.9%-～34.5%. Under natural rainfalls, the effects varied rainfall pattern. When the rain was short in duration and low in intensity its effects reached the highest, with runoff and sheet erosion reduced by 62.1% and 72.0%. But when the rain was long in duration and high in intensity, it reduced runoff and sheet erosion by 26.3%and 58.3% and when the rain was short in duration and high in intensity, it did by 41.0% and 69.6%, respectively. Under the same standing time and soil tillage condition, its effect of reducing sediment yield was higher than that of reducing runoff. Under the condition of 6, 8 and 14 m s^-1 in wind speed, it reduced wind erosion by 25.0%～64.6%, 31.0%～52.9% and 24.5%～43.2%, respectively, as compared with those in the control treatments. Manual tillage significantly increased water and wind erosion. Besides the effects of spraying corn stalk sap on various types of erosion varied with standing time and tillage. By increasing soil shear strength and soil hardness, promoting formation of soil micro-aggregates, spraying corn stalk sap reduced soil erosion of any types. After spraying corn stalk sap, soil disintegration decreased by 97.4%～98.5%; soil shear strength and soil hardness increased by 98.1%～171.2% and 11.4%～127.5%, respectively; proportion of soil aggregates with diameter < 0.25 mm decreased by 46.9%～51.6%; and proportion of soil macro-aggregates with diameter > 2 mm increased by 88.1%～129.7%. 【Conclusion】Corn stalk sap is proved to be a practical soil amendment for control of water and wind erosion of the soil. It is, therefore, suggested that spraying of corn stalk sap be finished without suspending, so as to avoid any further human disturbance of the soil sprayed with corn stalk sap.