A thermo compressor was proposed by using gap clearance regenerator between piston and cylinder. The impacts of the filling pressure, heating temperature, dead volume, gap clearance and working substance on the thermo compressor were analyzed by the simulation program. The prototype linear motor driven thermo compressors were setup and the characteristics were acquired by experiments. The peak-peak pressure in the system was influenced by the connecting line, regenerator, gap clearance between piston and cylinder, heating temperature. Helium4 as working substance performed better than Nitrogen. The peak-peak pressure could reach 0.412 MPa and the pressure ratio reach 1.46 when filling pressure was 2.2 MPa, heating temperature was 650°C and cooling temperature was 40°C.