Soil acidification severely suppress the crop production. Lime amendment is the main approach to control acidified soil, but the excess input of lime causes adverse impacts like soil compaction. In order to develop environmental-friendly amendment, a phosphorus(P) modified-biochar composite (ROP) was prepared from rice husk and oyster shell powder, and pot experiment was set to investigate the effects of ROP addition on the properties of acidified soil and the growth of Chinese cabbage. Results indicated that the addition of ROP could mitigate soil acidity. In soils adding 50 g/kg ROP and two different doses of fertilizers, the soil pH was increased from 4.20±0.02 and 4.39±0.21 to 6.48±0.09 and 6.00±0.04, respectively. Meanwhile, the concentrations of organic matter and nutrients like P were increased in ROP amended soils as well as the activities of phosphatase and urease, and the concentrations of available heavy metals were decreased. For Chinese cabbage, the dry weight of aboveground parts of plants in ROP treatment was 4.5 times higher than the control, and the concentrations of N, P and K were increased by 13.4% - 31.6%、119% - 141% and 28.5% - 81.1%, respectively. In conclusion, the application of ROP can improve the soil quality, and alleviate the threaten of soil acidification to plant growth. The findings provide scientific supporting to the remediation of agricultural soils.