The invention discloses a multilayer assembled anti-explosion sample thermostat, applied to the heating of petrochemical samples at the constant temperature. A constant-temperature base plate, a sample tube constant-temperature plate, a heating belt constant-temperature plate and a constant-temperature panel are arranged oppositely in sequence and are fixed together by fastening bolts. A right electric heating belt is arranged between the constant-temperature base plate and the sample tube constant-temperature plate, a sample constant-temperature tube is arranged between the sample tube constant-temperature plate and the heating belt constant-temperature plate, and a left electric heating belt is arranged between the heating belt constant-temperature plate and the constant-temperature panel. The right electric heating belt, the sample constant-temperature tube and the left electric heating belt are embedded in grooves of metal plates at two sides. Two ends of the right electric heating belt, two ends of the sample constant-temperature tube and two ends of the left electric heating belt are arranged outside the metal plates. The invention has the following effects of increasing heating area and improving heat efficiency by taking metal plates as heat transfer media and taking the anti-explosion electric heating belts as heat sources and embedding the metal plates and the anti-explosion electric heating belts in the grooves of the constant-temperature plates. In comparison with a liquid heat transfer medium, the multilayer assembled anti-explosion sampler thermostat does not need special seal and does not have the problem of the leakage of the liquid heat transfer medium.