Thickness measuring device and method based on continuous laser

The invention discloses a thickness measuring device and method based on continuous laser. The device comprises a laser source, a signal generation unit, a rotating polygon mirror, a rotating mirror control unit, a convergence unit, a signal acquisition unit, a signal processing unit and a control unit. The signal generating unit outputs a driving signal to the rotating mirror control unit, the rotating mirror control unit controls the rotating polygon mirror to rotate, and the signal generating unit triggers the laser source to output a laser beam to the rotating polygon mirror; laser beams are reflected to the converging unit through the rotary polygon mirror and are converged by the converging unit to scan on the surface of a detected sample along the direction perpendicular to the optical axis of the converging unit, the detected sample is stimulated to emit ultrasonic signals, the signal acquisition unit acquires the ultrasonic signals and transmits the ultrasonic signals to the signal processing unit, a