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D.F. Wang, X.M.Cui, G.Y. Gao, Z.Z. Huang, B.Z. Hu* This paper was selected for presentation by an SPE Program Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Papers presented at SPE meetings are subject to publication review by Editorial Committees of the Society of Petroleum Engineers. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Write Librarian, SPE, P.O. Box 833836, Richardson, TX 75083–3836, U.S.A. Telex, 163245 SPEUT. Abstract 'Qing You' long stroke pumping unit is a high velocity pumping unit. It is designed to achieve a large pump output of more than 200 m3/d with the diameter of rod pump less than 70 mm, and the annulus test can be conducted in the course of production. Based on the analyzing of some pumping unit commonly used in oil field and the relationships between acceleration and various parameters, in this paper, the design considerations was presented. The maximum velocity of the new developed pumping unit is about 40% higher than the recommendation for of common pumping unit, and its maximum acceleration is in the range of that of the conventional ones. Introduction In order to ensure the stable and high output of oil well, it is necessary both to apply advanced oil-production techniques to increase single-well output, and moreover conduct annulus test in the course of production to understand the production characteristic. The applications of large diameter pumps or submersible electric pumps are widely used to increase single-well output. However, with the pump diameter increasing, the annular access becomes smaller, and the annulus testing channel will be clogged. Therefore, the annulus test under normal operating conditions can't be conducted to obtained downhole data. Consequently, this may lead to difficult in the dynamic analysis of oil well. So, it is an urgent need to develop a new type of mechanical equipment which can produce high output and provide enough annulus access to conduct the downhole test. As discussing above, if the pump diameter is limited to less than 70mm, and the average production should be larger than 200 m3/d, the new type of pumping unit must be a high velocity unit, the average velocity of polished rod should be reach to about 2. 4m/s, the product of stroke length S and pumping speed N is required to be more than 72m/min (S N 72m/min). P. 821