Under the new situation that the ways to obtain the oil and gas exploration right has been reformed from the previous application first,"no cost"acquisition to open competition through bidding,auction,listing and"the one with the highest price or the best evaluated bidder obtains",it is urgent to establish a set of block value evaluation techniques and methods for oil and gas exploration right,determine the value of the granting block,and formulate a bidding scheme to obtain the exploration right by open competition.Aiming at the uncertainty of oil and gas geological conditions,exploration and development technology,market and other aspects in the exploration and development of oil and gas mineral resources,this paper puts forward an economic evaluation method of discounted cash flow based on Monte Carlo simulation.According to the uncertainty of expected oil and gas resources,exploration and development investment,operating cost and sales income,this method can obtain the value of the granting blocks under different probability conditions and then provide a basis for the preparation of bidding scheme.This method has been applied to the value evaluation of the granting block of oil and gas exploration right in Tarim Basin,Xinjiang.Corresponding to different competitive quotations,the probability of occurrence for enterprise's internal rate of return is calculated respectively.When the quotation is 485 million yuan,it is estimated that the probability of the internal rate of return exceeding 8，is 75.4，.Ultimately,the exploration right of the granting block was clinched a deal with 485.32 million yuan,indicating that the evaluation method is feasible.The economic evaluation method of discounted cash flow based on Monte Carlo simulation provides decision-making basis for enterprises to adapt to the competitive granting policy of oil and gas mining right,and has important practical significance for enterprises to openly compete for oil and gas mining right.