<p>The subsurface karst reservoirs in the Tahe Oilfield of the Tarim Basin have the richest oil and gas production, making it the largest karst fracture-vug type reservoir in China, among which the epikarst reservoir is an important category. By comprehensively utilizing core samples, thin sections, and logging data, and combining the characteristics of modern karst and paleo-karst outcrops, the characteristics of the underground epikarst reservoirs in the Tahe Oilfield have been summarized, and a comprehensive evaluation method has been established to identify favorable reservoirs. Under conditions of similar dissolution potential, the genetic mechanisms and developmental characteristics of epikarst exhibit significant differences across four facies units: solution hills, solution peaks, valleys, and depressions. The solution hill represents the most favorable facies in epikarst, followed by solution peaks, with valley and depression being the least favorable. By using the method of multiple linear regression, a quantitative evaluation formula is established based on four parameters: the type of reservoir space, the thickness of the epikarst reservoir encountered by a single well, individual facies area, and the porosity. This formula evaluates the differences of reservoirs in different facies units, clarifies the favorable distribution range, and provides important guidance for new drilling wells and water injection to improve oil recovery.</p>