Abstract: Al-Zn alloy coating is sprayed on 5083 aluminum alloy by thermal spraying. The electric conductivity of the coatings of different thicknesses are tested by electric conductivity tester and the thickness of the coating tested by metallographic method. Then, the coating thickness and electric conductivity are compared and analyzed by least square method. The relationship equation between thickness and conductivity of the coating is established, and the thickness of coating calculated by conductivity is compared with that measured by metallographic method. The results show that the thickness of thermal spayed Al-Zn alloy coating on 5083 aluminum alloy matrix is linear to the reciprocal of electrical conductivity, the thickness of coating calculated by conductivity is in good agreement with that measured by metallographic method. The calculation error is less than 5% in the thickness range from 193 μm to 317 μm.