Growth and nutraceutical quality of perilla sprouts is strongly dependent on planting density. This study explored the influence of planting density on growth, photosynthetic parameters, antioxidant capacity, main secondary metabolites, soluble sugar and soluble protein contents of ready-to-eat sprouts. Planting at a density of 1450 plants m−2 significantly increased yield, improved the activities of antioxidant enzymes SOD and CAT, enhanced the generation of reactive oxygen species, increased the content of total chlorophyll and net photosynthetic rate, and decreased the content of MDA in perilla sprouts. The content of flavonoids, volatile oil, soluble sugar and soluble proteins was highest when the density was 1450 plants m−2 compared to other groups. The relative contents of RA and anthocyanin in perilla sprouts reached the maximum value at planting density of 1887 plants m−2.