The utility model discloses a slide block type positive torsion oil pumping unit, aiming at solving the problems of high energy consumption, high motor power and large torsion of an output end of a reducer in the existing oil pumping unit. The slide block type positive torsion oil pumping unit is characterized in that a guide rail (14) is arranged on a support (15) in the vertical direction, a speed reducer (3) is connected with an input shaft of a speed increaser (5) through an oil pumping crank(4), an output shaft of the speed increaser (5) is connected with a secondary balancing weight (6), the revolving speed of the output shaft of the speed increaser (5) is two times of the revolving speed of the input shaft of the speed increaser (5), a lag angle Theta is arranged between the secondary balancing weight (6) and the oil pumping crank(4), a fulcrum bar (7) is connected at the upper part of a box body of the speed increaser (5), the other end of the fulcrum bar (7) is connected with a slide block (8) which can slide up and down along the guide rail (14), after a flexible oil pumping rope (13) goes through a movable pulley (11) at the upper part of the slide block (8), and the other end of the flexible oil pumping rope (13) is fixed on a beam (10). The slide block type positive torsion oil pumping unit has the characteristics that the energy consumption is low, the output torsion value of the reducer can not be negative, and the fluctuation is little.