In order to investigate effect of on-farm seed priming and weeds control on yield, yield components and harvest index of a corn hybrid, an experiment was arranged factorialy in a complete randomized block design with three replications in 2010. In the experiment investigated two factors, priming (in four levels including no-primed, priming with urea solution, priming with zinc sulfate solution and priming with tap water) and weed control in three levels (including no-weeding, weeding in 20 days after planting and weeding in 20 and 40 days after planting). For on-farm priming the seeds were placed for 16 hours in solutions of urea (6 g/l), zinc sulfate (0.34 g/l) and tap water, and planted after surface drying in the soil. The results showed that weed control caused an increase in grain numbers in corn and seed priming with urea solution in once weed control had higher 100 grains weight. Priming treatments with urea and zinc sulfate solution showed the highest grain yield and had no significant difference at one and two-times weeds control after planting, no significant difference was between zinc sulfate priming with one weed control and no- primed with two-times weed control. That priming with zinc sulfate solution could decrease weed interference and its control costs by increasing corn competition ability. Generally in all of no-weed control plots except in primed with zinc sulfate solution the lowest grain yield was obtained. Also harvest index was highest in plants that was primed by tap water.