Abstract: In order to solve the problems of poor soil and shortage of guest soil for ecological restoration of gold mines in the arid steppe region of Northwest China,an experimental study on soil modifier vegetation restoration using biomass materials as soil modifier prepared from agricultural solid waste corn straw as raw materials was carried out.By analyzing the changes in pH,nutrient composition,and water retention capacity of modified soil,the modification mecha-nism of biomass materials on the restoration matrix was explored.Ryegrass,tall fescue,and dogtooth root are used as modifiers to verify the modification effect of biomass materials on poor soil.The results showed that biomass materials contain a large amount of humic acid and fulvic acid,which can significantly reduce the saline-alkali property of topsoil matrix,soil pH value decreasing from 8.80 to 7.39,and the pH improving significantly with the increase of the added proportion;the addition of biomass materials promoted the formation of soil aggregates with large particle size,soil bulk density decreased significantly,soil water retention capacity increased,and soil nutrients and organic matter contents increased significantly;the biomass of ryegrass,tall fescue and dogtooth root was the highest when the biomass content was 10 %-20 %,and the leaf width and plant height were better.