In order to evaluate the effects of living mulch of common vetch (Vicia sativa L.) on yield and yield components of maize (SC.704 cultivar), experiment was conducted as a split-split plot based on randomized complete block design with four replications in Meteorology Station of Fars province, city of Firoozabad, Iran during 2015. Time of suppression of living mulch of common vetch (4, 6 and 8 leaf stages of corn using 2,4-D herbicide with the amount of 750 ml ha^-1) was arranged in main a plot and common vetch density in three levels (10, 20 and 40 plants m^-2) with two levels of no weeding and weeding were implemented in sub-plots. Results indicated that suppression time and living mulch density had a significant effect on seed yield, but their interactions were not significant. The results showed that suppression of living mulch at stages of 6 and 8 corn leaves led to minimum (9.5 ton ha^-1) and maximum (11.8 ton ha^-1) seed yield, respectively. Among the used treatments, weeding at the whole season and weedy check in the season showed the highest seed yield (13.141 ton ha^-1) while non-weeding showed the lowest seed yield (8.942 ton ha^-1). Suppression time and density of vetch living mulch had significant effect on ear number per plant, ear length, ear diameter, number of rows per ear and number of grains per row. Overall, the results demonstrated that living mulch application at density of 10 plant m^-2 and its suppression at the 6 leaf stage of corn were increased yield.