The invention relates to the sealing technology of low-temperature sensors, in particular to a method for sealing a low-temperature sensor. According to the method, a measurement line 1, a measurement probe 2, an alundum tube 3, a ball head sealing base 4, thermosetting resin sealing and sintering filler 5 are adopted. The sintering and sealing technology that the thermosetting resin is adopted as the sealing filler is adopted, the thermosetting resin with the expansion coefficient at low temperature smaller than that of materials used by the ball head sealing base is adopted to be matched with the ball head sealing base, and the interior of the sensor is sealed and fixed through the sintering technology. Non-adhesive sealing resistant to a 24 MPa high pressure and 77 K low temperature environment is achieved. No adverse influences are generated for measurement indexes of the low-temperature sensor, and the method can become a method for sealing the kind of sensors. The sealing method solves the key technical problem about isolating and sealing of the interior of the sensor in a low-temperature state.