The invention relates to the field of soil heating restoration, in particular to a soil restoration electric heater using a thick film technology. The electric heater comprises a casing flange and a junction box flange arranged on the casing flange and connected with a junction box, and further comprises a tapered external casing matched with the casing flange and used for directly inserting an electric heating pipe into soil, a thick film coating arranged on an inner wall of the tapered external casing and connected with high-temperature wires arranged on the junction box to heat the soil. The electric heater employs the tapered external casing; resistance paste is printed on the inner wall of the tapered external casing using the rare-earth thick film technology; the tapered external casing can directly serve as a heating pipe; a mounted electric heating pipe is omitted; during mounting, the tapered external casing is only required to be embedded and powered on; the electric heater is simple to manufacture and can be manufactured by printing and sintering; compared with the original electric heating pipe, magnesium oxide is required first; then, a metal outer pipe is heated; airis heated and conducted to the hot tapered external casing; then the soil is heated; the soil is directly heated by heating the tapered external casing; and the thermal efficiency is high.