Abstract: The multiple areal interpolation methods to transfer social economic data from irregular grid to regular grid are discussed,the advantages and disadvantages of each method are outlined.The integration of Monte Carlo simulation and GIS is employed to realize the transformation of population from irregular grid to regular grid.The population statisticed in irregular grids(administration boundaries) are disaggregated into pixels to obtain the population surface by assigning different weight to different urban landuse types,then the population attached to each pixel is aggregated to regular grid.The experiment result indicates that the regular grids can represent the real situation of population distribution io the urban areas.And different resolution grids can be selected to aggregate the population to meet different requirement,and the population represented in the regular grids can meet the requirement of urban micro modeling and macro social economic data statistics.