In order to investigate the effect of plant density and Cycocel on quantitative characteristics and protein barley cultivar south the present experiment was conducted in a farm located in Hamidieh city in 2014-15. Experiment was conducted as a split plot in the form of statistical randomized complete blocks design with three replications. Plant density at three levels (300, 400 and500 plants per square meter) in the main plots and three concentrations of cycocel (zero, 1500 and 3000 ppm) in sub plots were compared. The results showed that the density treatment had a significant effect on yieldand grain yield components, biological yield, grain protein percent and the grain protein yield. The highest grain yield with an average of 500.73 grams per square meter of treatment 300 plants per square meter and the lowest with an average of 385.3 grams per square meter of treatment 500 plants per square meter was obtained, respectively. Also, the results showed that the use of cycocel significantly increased the number of spikesper square meter, grain yield, one-thousand grain weight and protein yield of grain compared to control. The highest grain yieldwith an average of 496l/3 gram per square meter of treatment 3000 ppm cycocel and the lowest with an average of 356/05 gram per square meter of the control treatment were obtained. In general it can be concluded, density of 300 plants per square meter as well as the use of3000 ppm cycocel had the greatest potential to achieve the maximum grain yield.