In order to explore the mechanism of woody peat cultivation on the high-quality tillage layer in the newly cultivated land in red soil and the improvement effects of woody peat over other organic materials on the new cropland in red soil, a field experiment was conducted to study the effects of different organic materials addition on soil physicochemical properties, microbial biomass in 0-20 cm red soil of arid land and rice yield. Six different treatments included:CK (without adding modified material), M₃₀ FS (woody peat 30 t/hm²+straw decay 3 t/hm²+limestone powder 3.75 t/hm²), M₁₅ FS (woody peat 15 t/hm² +straw decay 3 t/hm²+limestone powder 3.75 t/hm²), CFS (biochar 15 t/hm²+straw decay 3 t/hm²+limestone powder 3.75 t/hm²), OFS (organic fertilizer 15 t/hm²+straw decay 3 t/hm²+limestone powder 3.75 t/hm²), FS (straw decay 3 t/hm²+limestone powder 3.75 t/hm²).The results showed that:(1) Compared with the control, the addition of woody peat and organic materials significantly reduced the soil bulk density in tillage layer, improved the soil total porosity and pH. Soil fertilities were also increased after addition of woody peat and organic materials with the varying degrees of improvement, the contents of soil organic matter, total nitrogen, total phosphorus and total potassium increased by 36.41% to 88.53%, 2.22% to 37.78%, 6.25% to 93.75% and 27.57% to 85.60%, respectively,and ammonium nitrogen, available phosphorus and available potassium increased by 17.21%~134.85%, 1.42%~72.76%, 8.71%~156.79% and 12.99%~332.39%, respectively.(2) Adding woody peat and organic materials had a significant effect on soil microbial biomass in tillage layer. Compared with the control, the soil microbial biomass carbon and nitrogen increased significantly by 52.95% to 219.00% and 121.45% to 548.73% respectively.(3) The rice yield increased significantly with the application of woody peat and organic materials, of which M₃₀ FS gave the biggest increase of 39.53% in production. (4)The soil quality of cultivated land under different treatment was divided into 3 grades by cluster analysis:first grade (M₃₀ FS), second grade (M₁₅ FS, OFS, CFS), and third grade (FS, CK), among which soil quality level was the highest under M₃₀ FS. The addition of woody peat and organic materials could significantly reduce soil bulk density in tillage cultivated layer, alleviate the viscous and acidification in red soil through improving soil total porosity and pH, and increase the soil nutrient and microbial biomass carbon and nitrogen contents, improve soil physical, chemical and biological properties, and finally increase rice yield. In a word, the addition of 30 t/hm² of woody peat had the most obvious effect on the construction of high-quality tillage layers of new cropland in red soil.