Abstarct: In order to study the effects of plant density, nitrogen source and planting pattern on yield of grain corn cultivar Ksc301 (Toloe), an experiment carried out in 1385 at fields of agricultural Research center of shahrood. The arrangement was split-split plot baxsed on completely randomized blocks design whit four replications. The main plots were allocated to three plant densities(70000,80000,90000 plant/ha), the sub plots include two source of fertilizers (urea and ammonium sulfat) and sub-sub plots consisted of two planting pattern(single row and twin row). For determining physiological growth indices sampling did every 15 day and growth indices calculated with mathematical quadratics. At the end of growth season, final harvest and analysis were did. In conclusion this experiment showed that plant density affected grain yield, biological yield, plant height, height ear length and diameter and stem diameter but number of row, kernel per row and harvest index. Grain yield in 80000 and 90000 densities was at the same level and were better than 70000 density. Differences between 80000 density with respect to 70000 density was 13%. In this experiment, two sources of fertilizer can not affected any upper propertis. The results showed planting method significantly affected the grain yield, number of kernels per row, biological yield plant, height plant, first ear height, ear diameter and length and stem diameter. Grain yield in twin rows was 8% upper than single row. Interaction between plant density and planting method affect grain yield, biologic yield, plant height and ear height. Affected some of treatment levels too. Leaf area index and crop growth rate affected with plant density and Crop planting method. The highest NAR obtained from lowest level of plant density and thus at twin row. RGR in 70000 density was slower, but twin row compared to single row was better. Fertilizer source could not affected any indices. All treatments could not effected harvest index....