Using simulation models with long term meteorological data application is one of the ways of determining the best crop planting pattern. This research was performed in order to determine the best density and sowing date in rainfed wheat (Sardari cultivar) under Urmia environmental condition by using SSM-Wheat model. Selective scenarios were: eleven sowing date (July 28, August 13, August 28, September 12, September 27, October 12, October 27, November 11, November 26, December 11 and  December 26) and seven plant density (375, 400, 425, 450, 575, 500, 525 plant/m²) for 3 years (2009-2011) in Urmia environmental condition. Results showed that density did not have any significant effect on phenological traits; but sowing date caused main changes in them. In the other words, the number of days to maturity decreased about 141 day by switching sowing date from July 28 to December 26. Maximum leaf area and leaf area index significantly decreased at the beginning of seed growth because of plant density increase. Besides, the node number in main stem, crop mass in grain filling period and portioning coefficient were affected by the sawing date. Results showed maximum grain yield and harvest index were obtained in September 12 sowing date and 425 plant/m² planting density. Therefore, in order to obtain higher yield achievement in the abovementioned region, planting in the last one third of September and 425 seed rate per square meter should be considered in future researches