An intelligent instrument for coating thickness measurement has been developed by using X-ray fluorescent and modern microcomputer techniques. This paper discribes the principle and the construction of the instrument. The instrument allows fast

precise and nondestrustive measurement of the thickness of various coating plating on metallic or nonmetallic parts. For example

the range of the thickness measurement for magnetic coating layer of the magnetic disc is M=50—500µg/cm

2

the precision of coating thickness measurement is better than ±4% (M=100µg/cm

2

).