Abstarct: Nitrogen fertilizer is usually a positive effect on yield and yield components of cereal and is especially in corn. Appropriate use of fertilizer can have a positive effect on plant yield. Acid humic as an organic acid derived from humus and other natural resources through hormonal effects and improve nutrient uptake, root and shoot biomass is increasing. In order to investigate the effect of nitrogen application timing and humic acid on yield and yield components of corn and weed, a factorial experiment in randomized complete block design with three replications was conducted in 2011 at the Faculty of Agriculture Shahrood University of Technology. The N was used as (A1) no N application, (A2) application of 1/3 of the total N at the planting time +1/3 at the 6-8-leaf stage +1/3 at the tassel stage, (A3) no N application at the planting time, 1/2 at the 6-8-leaf stage +1/2 at the tassel stage, and (A4) 1/2 at the planting time and the rest of N at the tassel stage as the first factor, application of two levels of humic acid, control (no application) and 1.25 lit per 100 kg seed used as the second factor and weed control in two levels (weed free and weed infest) as the third factor. The results showed that split application of nitrogen significantly affected the weight of ear, number of seed rows in ear, hundred seed weight, ear wood diameter and dry weight, grain yield, biological yield and density and dry weight of weeds.Weed control indicated that all the studied traits except plant height, hundred seed weight and harvest index had a significant effect. humic Acid effect was significant only on the number of seed row in ear The results showed that the highest values of nitrogen use traits of maize treatments used at planting + 1/2 in the 6 to 8 leaf steag +1/2 was obtained at the time of tassel steage The least deansity and dry weight of weed control was obtained (without N) belongs to the A3 no use of nitrogen at planting + 1/2 in the 6 to 8 leaf stage + use 1/2 at the time of tassel stage.The study is baxsed on nitrogen fertilizer application timing and application of acid humic on the growth of corn, and competition with weeds and ultimately has an impact on corn yield.