This study was conducted to determine the effects of different plant densities on source -sink characteristics and grain yield of the compact-type maize variety Chaoshi No.1 grown in Spring season in a super-high yielding paddy field．The results showed that, with the increase of plant density, the population leaves area index (LAI) and the dry matter accumulation (DMA) increased, while the chlorophyll content (SPAD value) and specific leaf weight (SLW) of leaf decreased. On the other hand, the grain number per ear and 100-grains weight decreased with the increase of plant density. Therefore, the sink volume per plant would be dropped with the increase of plant density. The highest grain yield was obtained under the plant density of 9.67×104 plant/hm2, which was significantly higher than that of the other two treatments by 7.3% and 7.1%, respectively. Ratio of grain number to leaf area was decreased gradually with the increase of plant density. Output percentage of stem-sheath and leaf store matter were negative, however, the differences in the output percentages of stem-sheath and leaf store matter were not significant among different planting densities. In silking and milking stages, population LAI was positively related with grains yield but negatively with grain weight per plant and dry weight per plant. Both specific leaf weight and SPAD valve were positively related with grain weight per plant and dry weight per plant. Ratio of grain number to leaf area was positively related with grains per ear, grain weight per plant and dry weight per plant. Output percentage of stem-sheath store matter was negatively related with 100-grain weight and dry weight per plant.