The invention discloses a method for measuring the thickness of a thin film through an atomic force
microscope assisted by a low-power
optical microscope, which comprises the following steps of: pre-aligning the tip of a probe of the atomic force
microscope with a step of a sample to be measured by virtue of the low-power
optical microscope, and then controlling the tip to descend to a first height of the surface of the step; the needle tip is lifted under real-time monitoring, the needle tip and the surface of the sample are located in the focal plane range of the low-power
optical microscope, the position of the probe is adjusted, and the projection of the needle tip is located over the step to complete accurate positioning. Starting a linear scanning mode, carrying out single-
line scanning in a direction perpendicular to the step extension direction, dynamically adjusting scanning range parameters until a scanning curve presents a step-shaped characteristic, adjusting the scanning curve to a view center, switching a line-by-
line scanning mode to obtain three-dimensional shape data, and obtaining the film thickness of the to-be-detected sample based on the three-dimensional shape data. According to the method, the probe and sample positioning process is optimized, scanning parameters and a
data processing method are reasonably set, and the problems of long time consumption and low precision of measuring the film thickness by the atomic force
microscope under the assistance of the low-power light microscope are effectively solved.