The invention discloses a PEA space charge measurement system under a full-size high-voltage direct current cable temperature control gradient. The system comprises a direct current cable insulation layer temperature gradient control device (2), an electrode system (3), a PEA space charge measurement device (4) and an external measurement control device (6). The direct current cable insulation layer temperature gradient control device is provided with a closed space surrounding a test cable, the electrode system (3) is connected to the test cable inside the closed space and is connected with a high-voltage impulse source (5) outside the closed space through a wire, the PEA space charge measurement device (4) is connected to the electrode system (3), and the external measurement control device (6) is located outside the closed space and is connected with the PEA space charge measurement device (4). The PEA space charge measurement system and method are used for space charge measurement of an insulation layer of a full-size high-voltage direct current cable under the temperature control gradient in the research and development test period, the prequalification test period, the load cycle test period and the long-term aging test period, and the high resolution ratio and measurement precision can be achieved.