Greenhouse agriculture refers to crop cultivation conducted in an artificially protected environment, also known as protected cultivation. Currently, China has the largest area of agricultural facilities in the world, exceeding 85% of the world's total. Greenhouse cultivation is prone to problems such as soil compaction, nutrient imbalance, and secondary salinization (Yang 2018). In soils with secondary salinization, not only is nutrient utilization efficiency and microbial activity low, but crop yield and quality are also poor. Furthermore, after the aggregate structure of greenhouse soil is destroyed, it exacerbates soil compaction, affects gas–liquid circulation in the soil, and leads to the deterioration of the soil environment, severely hindering the green and sustainable development of greenhouse agriculture. At present, the use of bio-organic fertilizers or soil conditioners to improve soil quality has received widespread attention. There is an urgent need for efficient methods of co-applying organic fertilizers and soil conditioners to improve soil structure, reduce salt accumulation in the surface soil, balance soil nutrient content, improve the soil rhizosphere environment, and enhance soil quality. This chapter investigates the application of a soil conditioner prepared from food waste mixed with bio-organic fertilizer to secondarily salinized greenhouse agriculture soil. It studies the improvement effects of the combined application of organic fertilizer and soil conditioner on issues such as nutrient imbalance, high salt content, and low microbial community activity in greenhouse soils. The study elucidates the mechanism by which the combined fertilizer application ameliorates secondarily salinized soil, providing new ideas for its remediation.