To investigate the effect on Zn spraying and plant density on seed yield and morphological characteristics of Green gram an experiment was conducted in summer 2011 in Koohdasht. Experiment was performed in split plot randomized complete block design with three replicates. Zn spraying was considered on three levels with no spraying, once spraying in a rapid growth phase, two times spraying with two in thousand concentration of Zn fertilizer. The results showed the superiority of the length of main stem’s pod number, main stem node number, node number of lateral stem and seed yield was obtained in the method of spraying. Analysis of variance showed that the effect of plant density on seed yield, plant height, pod length in main stem and main stem node number was significant and the highest yield of 1787.5 kg/ha was related to the density of 33 plants per square meter and once spraying and this treatment is justified for the region.