Abstract: With the constant development of metropolitan area in China and the demands of armed police's function task, it is necessary to build a military-civilian reconciled oil reserve system based on the situations of well-developed traffic network system, perfect infrastructure and dense network of gas stations in metropolitan area. Drawing on the "virtual reserves" idea, by combining the methods of cluster analysis, qualitative analysis and quantitative analysis, the mathematical model for site selection of oil reserve tankfarm in metropolitan area was established, and MATLAB was used to solve the problem to optimize the location of oil reserve tankfarm, and inventory and storage quantity of oil reserved in each tankfarm. The example shows that the oil reserve model based on metropolitan area can solve the problem of optimization of layout of oil reserve tankfarm and it is of good reference to solve the problem of oil reserve guarantee in metropolitan area.