Based on mathematical programming models and the concept of linear programming, this paper uses and aimed at presenting an optimized model for establishing and developing complex pulp and paper factories with an annual production capacity of 75,000 MT. Regarding limited resources and variable cost of factors of production, including raw materials, such as various chemicals used in the process, additives and conifer fibers, labor force, potential demand, and the lead time for the production of one ton of the product from cereal straws, an optimized model is presented with the purpose to maximize annual profit. Studies show that over 1.7 million tons of cereal straw are produced annually in Mazandaran Province. If %20 of the straw produced may be used as raw material in the intended paper industries, it will be possible to found two pulp and paper factories with a production capacity of 50,000 MT of chemical pulp (soda process), 80,000 MT of writing and printing paper and 75,000 MT of neutral sulfite semi chemical pulp (NSSC process) and 108,000 MT corrugating medium (fluted paper). Newsprint production is not economic and profitable. Raw material is the most important limiting factor in determining the economically reasonable scale of production.