Catch crops with economic value are easy to popularize and have good effects on controlling nitrogen and phosphorus leaching losses during leisure time, thus are of great significance for reducing nitrogen and phosphorus losses from greenhouse vegetable soils in the Pearl River Delta Region in China. In this study, the leaching tube method was used to study the effects of planting four kinds of edible amaranth (round red amaranth, heart red amaranth, green amaranth and Nanxing amaranth) on pH, inorganic nitrogen and phosphorus concentrations of soil leaching solution, and the available nutrient contents in greenhouse vegetable soil after vegetable harvest during summer fallow period (from July to August). The results showed that the economic benefits of planting amaranth ranged from 20 400 to 28 300 yuan/hm². At the same time, planting amaranth reduced the concentrations of NO₃^--N, NH₄⁺-N and total P in soil leaching solution with the average efficiencies of 31.2%-49.5%, 35.5%-37.5% and 30.1%-43.6%, respectively. Compared with the fallow control treatment, no depletion was observed in the concentrations of available phosphorus and alkaline hydrolysis nitrogen in the soil after amaranth harvest, while the concentration of available phosphorus increased by 31.9%-68.1%. The results indicate that planting amaranth as catch crop is an optimal technology, which can reduce soil nitrogen and phosphorus leaching losses during the vegetable fallow period and produce certain economic benefits without affecting soil fertility for subsequent vegetable production.