To precisely measure the thickness and thickness distribution of a self-supporting metal film, the measurement technology based on a chromatic confocal spectral sensor was established. The measurement principle and system structure were descripted in detail, and the measurement uncertainty was analyzed. The thickness and thickness distribution of the self-supporting metal film with the thickness between 10-100 μm were tested using the sensor group, precise displacement platform and precise calibrated samples. The measurement uncertainty was evaluated based on analysis of sensor accuracy, the uncertainty of calibration sample thickness, the positioning accuracy of two sensors and the system repetition uncertainty. Experimental results indicate that the measurement uncertainty is about 0.12 μm,which satisfies the requirements of Inertial Confinement Fusion(ICF) for target parameter measurement in high stabilization, high precision and non-destruction.