The minimum economic effective thickness of a single well refers to the minimum effective thickness that can recover all the investment, operating costs, disposal costs and related taxes and frees generated in the exploration area during the life period of a single well in the process of reserve estimation. It is an important basis for delineating the oil-bearing area and ensuring the economy and availability of reserves. The difference between the current calculation method of minimum economic effective thickness and the standard do not consider the differences of three different reserve levels, which leads to the indicated goelogical reserve and inferred goelogical reserve share the same high starting requirements with measured reserve. Based on the break-even method, the minimum economic effective thickness chart of single well of measured reserves under different zones, different well depths and different oil prices in Junggar Basin is established by analyzing the geological characteristics, development methods, investment and cost levels of 582 measured geological rserves. On the basis of this minimum economic effective thickness chart and comprehensively considering the probability and upgrade rate of three-level geological reserves to economically recoverable reserves. The minimum economic effective thickness of the indicated reserves is estimated according to 70% of the measured reserves, and the minimum economic effective thickness of the inferred reserves is estimated according to 50% of the measured reserves. This strating standard of the three-level geological reserves will provide an evaluation standard for the economic development of three-level reserves.