Abstract: The effects of different planting densities on the growth dynamics, agronomic traits and grain yield of Quandou No.13 were investigated in this paper in order to select the optimal planting density, thus to provide the theoretical basis for the high-yield cultivation and the demonstration promotion of Quandou No.13. The single factor 6 levels of hill spacing including (M1) 9.5, (M2) 11.1, (M3) 13.5, (M4) 18.5, (M5) 22.2, (M6) 33.3 cm were used for the random block design, and the results showed that:the plant height, dry matter weight and leaf area index of Quandou No.13 were significantly affected by the planting density. The correlation analysis of planting density with the agronomic traits and the yield showed that the planting density was positively correlated with the plant height and the bottom pod height, and significantly negatively correlated with the node number of main stem, the effective branch number, the effective pod number per plant, the grain number per plant and the grain weight per plant, while significantly positively correlated with the yield. The yield levels under each treatment were in the order of M2>M4>M1>M3>M5>M6. The yield under M6 treatment was minimum, reaching 2007.5 kg·hm^-2, which was significantly lower than that under other treatments. The yield under M2 treatment was maximum, reaching 2745.0 kg·hm^-2, which was significantly higher than that under M5 treatment, but had no significant difference with those under M4, M1 and M3 treatments. In the actual production, it was suggested to plant Quandou No.13 with a hill spacing of 18.5 cm (M4), and the corresponding planting density was 222000 plants·hm^-2.