The invention provides an active-cooling vacuum-sealing focal plane assembly of a space camera. Via the assembly, a detector can be cooled below -60 DEG C, and the problem that a traditional focal plane detector of the camera causes steam pollution during cooling is solved. The assembly comprises a focal plane case trimming pad, a clamping ring, a vacuum glass window, a vacuum focal plane case, a vacuum sealing connector, a cooling assembly, a focal plane case pedestal, a focal plane case base plate, heat tubes, a relay box, thermistors and thermoelectric coolers, the vacuum glass window seals and compresses a light inlet via the clamping ring, and the focal plane case trimming pad is arranged in the front end of the clamping ring; the cooling assembly comprises a cold screen window, a cold screen, an active cooling CCD assembly and a cold screen base plate; the cold screen window is installed in a gap of the cold screen; the back side of the cold screen base plate is provided with the thermistors and thermoelectric coolers; and the cooling assembly, the focal plane case pedestal, the focal plane case base plate and the heat tubes are all arranged in a cavity formed by the vacuum focal plane case and the relay box, and the heat tubes are arranged in the back side of the focal plane case base plate.