The invention provides an HVDC line corona current measuring system used in a high-altitude area. The HVDC line corona current measuring system comprises a remote end subsystem and a local end subsystem, wherein the remote end subsystem is arranged at a high-altitude DC power transmission line side, and the local end subsystem is arranged at an upper level control center; the remote end subsystem comprises a corona current acquiring module, a humidity detecting module and a temperature control module which are connected with an integrated control processing module; the local end subsystem comprises a data integrated processing platform; and the integrated control processing module is connected with the data integrated processing platform through an optical fiber. Compared with the prior art, the HVDC line corona current measuring system used in the high-altitude area provided by the invention can adapt to corona current measurement in the high-altitude area under low temperature condition, can control the internal temperature of the remote end subsystem, guarantees stable operation of the measuring system, and can prolong working time of the system.