The objectives of this research were to investigate the system of rice intensification (SRI) on early growth, grain yield, and yield components under Chinese milk vetch residue-mulched no-tillage cropping systems at silt loam soil. The field was prepared as a split-plot design with three replications, main plots consisted of Dongjinbyeo, and Sobibyeo as a cultivar, and subplots consisted of 10×10 cm, 20×20 cm, and 30×30 cm as a planting density. Weed infestation during rice growing season was more severe in wider planting density 30×30 at 35 days after transplanting (DAT), and 20×20 cm at 95 DAT in both Sobibyeo and Dongjinbyeo. The maximum plant height was recorded in Sobibyeo compared with Dongjinbyeo, 10×10 cm and 20×20 cm planting density compared with 30×30 cm from 20 DAT until 60 DAT. Among the three planting densities, SPAD values were significantly greater in planting density of 20×20 cm both in Sobibyeo and Dongjinbyeo followed by 30×30 cm compared with closer planting density of 10×10 cm. The lowest grain yield was observed in wider planting density of 30×30 in both Sobibyeo and Dongjinbyeo due to lower number of panicle per unit area. Our findings suggest that optimum planting density for SRI in no-tillage paddy was 20×20 cm and it should be useful the systems to small-scale rice farmers in Korea as a sustainable farming system.