Abstract: The effective usage of water resources is very vital to the Development of Western China, furthermore, the systematic program of water pollution control is its important part and the economic model is the foundation of the systematic program of water pollution control. Based on the natural conditions, the status of social economy and polluted water treatment of arid areas, the building and operating conditions in some industrial and mineral water treatment projects and urban sewage projects are investigated, and cost functions of pollution control projects are analysed and estimated, in which the coefficients are optimized in the complex methods, and finally the economic model is built. The results shows that the regional social and economic development levels, natural conditions, geographical locations, and scale and benefits of pollution treatment facilities in arid areas all have great influences on the economic model. Because of the special geographical locations and the social and economic development levels in arid areas, more costs for building the projects of water pollution treatment must be paid, such as costs of energy, transportation, technological spreading, in order to reach the same treatment effectiveness as the other domestic regions. In addition to the above, if the social and economic development levels and their burden capacity of economy in arid areas are taken into consideration, the work of water pollution treatment projects may involve in deteriorating circulation. Therefore there is necessity that the cost functions of water pollution treatment be studied in order to adjust to the sustaintial development in arid areas.

Key words: arid areas, water pollution, cost functions