The invention discloses a DC (direct current) 750V-3 kV flexible hanging section insulator. The DC 750V-3 kV flexible hanging section insulator is composed of an installing base I, an installing base II, an adjusting insulation bar, a contact wire insulation bar, a pair of connecting clamps, a pair of long slide plates, a pair of short slide plates, a pair of slide plate fixing brackets, a pair of contact wire dropper clamps; the adjusting insulation bar and the contact wire insulation bar are horizontally connected and fixed to the middle of the installing base I and the installing base II; a pair of connecting clamps are horizontally connected behind the installing base I and the installing base II, and installed and fixed at end parts of contact wires; a pair of long side plates and a pair of short slide plates are arranged at both sides of the installing base I and the installing base II in a staggering manner; moreover, the middle parts of the long side plates and the short slide plates are respectively fixed at both sides of the installing base I and the installing base II, and tail parts are connected and fixed to the contact wires through the contact wire dropper clamps. Through improving the structural form and the connection and fixation method of an insulation element, the DC 750V-3 kV flexible hanging section insulator improves the bearing force and safety coefficient of the section insulator. Besides, main parts of the section insulator can be installed and debugged in place before leaving factory, and are not required to perform the secondary adjustment in the course of installing on site, and thereby the installing step is simplified and the installing difficulty is reduced.