Land use optimization is one of the most important issues that has a big effect on soil conservation. In this project in order to achieve minimum soil erosion and maximum profit of different land uses, including forest, orchard, range, irrigated and dry farming land use, linear programming was used in Qazvin plain watershed. Three different scenarios of land use were designed: 1) existing land use, 2) existing land use with some land management, and 3) optimum land use with suitable land management. By using Lingo software, the optimum statues were determined. The results showed that the area of orchards (45% increased), irrigated lands (58% decreased), and dry lands (53% decreased) have to changed for optimization land uses, but the area of forest and rangeland did not need any changes. Also, the amount of soil erosion in existing land use, existing land use with land management, and optimum land use with suitable land management declined 4%, 30%, and 39%, respectively, while their profit increased 30%, 39%, and 40%, respectively. In addition, the results of sensitive analysis indicated that orchard and irrigated land are the most sensitive land uses in solving the problem.