Abstract: Soil quality of urban green space is an important factor affecting the vegetation landscape of green space,and biochar is known to have excellent potential for soil improvement application.The effects of biochar application on soil quality improvement and plant growth in urban green space were explored,through field experiments in Guangyang Valley Urban Forest Park in Xicheng District,Beijing.The results showed that,（1） The length and width of the leaves of quercus mongolica and acer saccharinum treated with biochar could grow by 3%—5% per month,which was only 1%—2% without biochar treatment.The rejuvenation effect of acer saccharinum was more significant.（2） The photosynthetic rates of quercus mongolica and acer saccharinum in the test group increased by 0.88% to 13.38% respectively compared with the control.The net photosynthetic rate of quercus mongolica applied with biochar showed a bimodal dynamic change,while that of acer saccharinum was a unimodal change.The difference between the net photosynthetic rate of the quercus mongolica test group and the control group was not significant,while the difference of acer saccharinum was significant from July10th.（3） The organic matter content of soil with biochar applied was enhanced by 6.04%,pH decreased by2.47%,conductivity decreased by 6.77%,and nutrients such as nitrogen,phosphorus,and potassium increased by 28.48%,10.05% and 3.10%,respectively.In conclusion,the application of biochar can improve the soil quality of green space and rejuvenat plants.