The problem of farmland acidification in China is widespread throughout the country, except for the arid northwest region. The situation is particularly prominent in the tropical and subtropical regions of the south and the black soil area of the northeast, causing serious harm to agricultural production and the ecological environment. Acidified red soils often suffers from multiple constraints such as acidity, sticky, and infertility, necessitating the urgent development of soil amendments capable of simultaneously addressing these multiple issues. This study compared the effects of applying biomass ash, biomass residue and their combined use with waste mushroom substrate on ameliorating soil acidity, compaction, and infertility in red soils through indoor incubation experiments. The amelioration effects of combining inorganic and organic materials were verified through field plot experiments. The results from the incubation experiments indicated that the application of both inorganic and organic materials, as well as the combination of inorganic and organic materials, increased soil pH, exchangeable Ca2+, Mg2+, and K+ content, while reducing exchangeable Al3+ content, thus ameliorate soil acidity. However, the amelioration effect of the combination of inorganic and organic materials is better than that of single application of inorganic materials, indicating that the combination of inorganic and organic materials has a synergistic effect on ameliorating soil acidity. The combination of inorganic and organic materials also increased the soil organic matter content. The results of field experiments further demonstrate that the combination of inorganic and organic materials not only ameliorates soil acidity and increases soil organic matter content, but also reduces soil bulk density and increases soil porosity, thereby increasing biomass and grain yields of canola. Therefore, the organic-inorganic composite amendment made from biomass ash or biomass residue with waste mushroom matrix has the comprehensive effect of ameliorating the acidity of red soils, enhancing soil fertility, improving soil structure, and eliminating multiple constraints such as acidity, sticky, and infertility. This article will provide theoretical foundation and technical support for the management of acidified farmland and the sustainable utilization of acidic soil resources.