Abstract: Four main controlling factors of the reasonable well spacing for medium?low permeability conglomerate reservoirs in Karamay oilfield are determined by means of mathematical statistics, reservoir engineering and characteristic model orthogonal experiment, etc. They are sand?body morphology, permeability variable coefficient, permeability and oil displacement efficiency. The weight variation regulation of these main controlling factors are found by multi?factor sensitivity analysis in different stages, and then the staging evaluation mathematic models for reasonable well spacing of medium?low permeability conglomerate reservoirs are developed. The case study verifies the accuracy of these models, which can provide basis for scientific evaluation of such a reasonable well spacing and further development adjustment in the future