The invention relates to an experiment segment based on a fusion and fission mixed pile water cooling cladding layer and an experiment method of the experiment segment. The experiment segment comprises a high-temperature resistance stainless steel pipe, an electric heating rod with a thermocouple at the inside, an electric heating rod without a thermocouple, cover plates, separation plates, pressure taking pipes and an inlet and outlet branch pipe, wherein the electric heating rods are respectively assembled in the high-temperature resistance stainless steel pipe, the cover plates are welded at the two ends of the electric heating rods, two stainless steel separation plates are welded in the high-temperature resistance stainless steel pipe, three armored thermowells are simultaneously welded outside the high-temperature resistance stainless steel pipe, the pressure taking pipes are respectively welded on the outer wall surface of the high-temperature resistance stainless steel pipe, three heating rods are placed at the left end of the experiment segment, four heating rods are placed at the right end, and the heating rods at the left end and the heating rods at the right ends are in crossed placement. By aiming at the experiment segment of the fusion and fission mixed pile water cooling cladding layer model manufacture, the flowing heat exchange condition under the structure is simulated, the experiment segment can be used at high temperature and high pressure, the sealing insulation performance is good, the results can be easily measured, the structure is compact, and the experiment segment is suitable for being assembled onto a nuclear reactor thermal hydraulic high-temperature and high-pressure experiment loop.