The invention discloses a maintaining and first-aid repairing pipe clamp for sealing a middle-high-pressure pipeline through light inner-expansion. The pipe clamp comprises two symmetrically-arranged light semi clamps of the same structure, an annular sealing rubber strip, axial sealing rubber strips, an agent injection valve, a semi clamp connecting bolt and nut assembly and a supporting adjusting assembly. Through manual extrusion deformation of the corresponding axial sealing rubber strips on the two light semi clamps, axial sealing of the pipe clamp can be achieved; the agent injection valve injects an injection agent into injection agent filling cavities of the light semi clamps, and the annular sealing rubber strip is pressed on a damaged pipeline to achieve circumferential seal of the pipe clamp, so that blockage of large-damage (cracking or punching) leakage of the middle-high-pressure pipeline can be achieved; and compared with an existing sealed cavity type pipe clamp, the weight can be reduced by more than 40%, the better pipeline deviation application is achieved, and the higher leakage blockage success rate is achieved; the sealing pressure is large and adjustable, the circumferential seal is even, the corrosion-resisting performance is good, mounting and adjusting are easy, convenient and labor-saving, and a diver can conveniently carry out underwater construction.