Abstract: Based on a combination of the microcosmic characteristics of present industrial oil and gas,viscous crude oil and reservoir bitumen,and the macroscopic geological settings in the middle area of Tarim basin,the authors studied the models for petroleum pool-forming and evolution in that region. It is indicated that the present oil reservoirs there had formed mainly in the Himalayan pool-forming stage,however,the oil and gas in the early-formed pools were preserved only in the forms of reservoir bitumen and redox residual oil,as they being damaged to different extents. The present oil/gas reservoirs mainly consist of marine oils of miscible sources from the northwest and marine condensate gas and dry gas from the northeast.