Oil and gas ascending velocity plays an important role in making next-step work plan during drilling operation. In this paper, the traditional formula of oil and gas ascending velocity is modified based on the analysis on previous experience and combined with the actual construction practice, and the parameters involved in the revised formula are analyzed one by one, the accuracy of each parameter in the formula is further improved without affecting the normal construction procedure. Through the field engineering test, this method is proved to be simple and practical with high calculation accuracy. This method can not only ensure the accuracy of the calculation results, but also has good maneuverability.