A device and a method for measuring the micro-zone spectrum of a phase-transformation film are provided. The device comprises a light source, a light diaphragm, a light chopper, a second dichroic mirror, a third dichroic mirror, an object lens, an imaging lens, a first lens, a first spectrometer, a first photoelectric detector, a phase-lock amplifier, a second photoelectric detector, a second spectrometer, a second lens, a third lens, an acousto-optic device, a fourth lens, an expander, a laser and a computer. The device can detect the micro-domain transmission spectrum and reflection spectrum of a sample to be tested before and after the laser-induced phase transformation under different laser excitation conditions including different laser power, pulse widths, repetition frequencies and action times, and can be applied in evaluating the micro-domain optical response characteristic and the photo-thermal stability of the phase-change film.