THIS STUDY WAS CONDUCTED IN 2008 AT THE RESEARCHRAL FIELD OF TEHRAN UNIVERSITY. THE EXPERIMENT WAS DESIGNED AS A RANDOMIZED COMPLETE BLOCK DESIGN WITH THREE REPLICATION. TREATMENTS WERE: ATRAZINE 1KG/HA, ALACHLOR 4KG/HA, ATRAZINE+ALACHLOR 1+4KG/HA, NICOSULFURON 80 G AI/HA, FURAMSULFURON 45G AI/HA, RIMSULFURON 25G AI/HA, NICOSULFURON+FURAMSULFURON (80+45G AI/HA RESPECTIVELY), NICOSULFURON+RIMSULFURON (80+25 G AI/HA RESPECTIVELY), FURAMSULFURON+RIMSULFURON (45+25 G AI/HA RESPECTIVELY), WEED INFESTS AND WEEDS FREE AS CONTROL. RESULTS SHOWED THAT ALL HERBICIDE TREATMENTA INCREASED CORN GRAIN YIELD AS COMPARED WITH THE WEED INFEST AND ALSO SHOWED THAT WEED FREE., ATRAZINE+ALACHLOR, NICOSULFURON AND FURAMSULFURON TREATMENTS, HAD MOST EFFECT ON INCREASE OF GRAIN YIELD. GRAIN YIELD IN DOUBLE-ROW PLANT PATTERN WAS MORE THAN SINGLE ROW PLANT PATTERN BUT GRAIN THOUSAND WEIGHTS IN DOUBLE ROW HAVE NOT SIGNIFICANT DIFFERENCE WITH SINGLE ROW PLANT PATTERN.