The invention relates to a pump for pumping drilling fluid in a mineshaft annulus in petroleum drilling, in particular to a centralizing underground annulus pumping screw turbopump, comprising an upper joint, a stator, a lower joint, a rotor and at least one centralizer of which the outer diameter is greater than that of the rotor; the lower end of the upper joint is fixedly connected with the stator or integrated with the stator; the exterior of the stator is sheathed with a rotor which can rotate opposite to the stator. The turbopump has reasonable and compact structure and convenient use; turbopump blades are protected through the centralizer outside the rotor; a spiral groove on the inner wall of the rotor is pushed by the circulating drilling fluid in the rotor to drive the rotor andthe external turbopump blades to rotate around the stator so as to discharge liquid in the mineshaft annulus, thus reducing the pressure of the liquid column in the mineshaft annulus in drilling operation, achieving the purposes of underbalanced drilling, improving drilling speed and efficiency and greatly reducing use of drilling liquid chemical agent to lower cost; and the turbopump is also characterized by simple structure, energy saving, environmental protection and convenient manufacturing.