Abstract: On the basis of production ratc calculation and analysis of eccentric horizontal wells, this paper discusses the typical Joshi formulas and the confusion of "+ "and "-" marks in them ,the influence of eccentricity on the caculated results with these formulas, the impact of gravity and cappilary force effects on the production rate of eccentric horizontal wells, and the delay of breakthrough time well .The understandings of production rate prediction and rational use of eccentric horizontal wells are deepened.