It is of great importance to prevent the quality deterioration of cultivatedlayer and reasonable improvement of the cultivatedlayer quality by analyzing the quality change characteristics, critical environmental impact factors and dividing the main obstacle types of the cultivatedlayer for red soil sloping land. Taking cultivatedlayer with typical planting system of the sloping farmland in red soil watershed as the research object, the quality change characteristics of the cultivatedlayer were analyzed by the method of cultivatedlayer quality index (CLQI), the obstacle types were defined and the key environmental factors’ function characteristics that affecting the cultivatedlayer quality were identified by the methods of clustering and principal component analysis, respectively. Results showed that the soil parameters characteristics of cultivatedlayer of red soil sloping farmland varied significantly, and the average thickness of cultivatedlayer was (18.88±3.17)cm, which was closely to the suitable thickness for crop growth. The soil saturated hydraulic conductivity was (3.39±2.6)mm/min, indicating that the soil infiltration and water holding capacity of the cultivatedlayer were slightly lower. The soil pH value was 5.06±0.64, which was faintly acidic. The soil with total nutrient content were poor and the quickacting nutrients were abundant. The cultivatedlayer quality was generally at a reasonable level of red soil watersheld, but existed degradation trend, with the reasonable degree (Ⅲ) of 72.2%, and unreasonable degree (Ⅳ) of 22.2%, and moderately degree (Ⅱ) of 5.6%. The CLQI of different slope positions was ordered as lower slope (0.482), upper slope(0.454) and middle slope (0.444). The cultivatedlayer types of red soil sloping farmland can be divided into six types of sticky knot type, nutrient infertility type, moisture restriction type, soil acidification type, no obstacle type and cultivatedlayer thinning type. Clay content, soil organic matter, soil saturated hydraulic conductivity, pH value and cultivatedlayer thickness can be used as diagnostic indicators of obstacle types for cultivatedlayer. The effective soil thickness, amount of fertilizer applied per unit sloping farmland area, slope direction and the tillage method were the key environmental factors which affected the cultivatedlayer quality of the red soil sloping farmland. Application of organic fertilizer, sub soiling and straw covering had obvious regulatory effects on improving cultivatedlayer quality. These results could provide useful parameter supports not only for the effective restoration and regular routes selection, but also for constructing the reasonable cultivatedlayer of red soil sloping farmland.