A note image acquiring system, comprises: a fiber laser, a fiber beam splitter, a fiber collimator, a laser beam expander, a lithium niobate intensity modulator array, a waveform generator, a signal amplifier, a polarization beam splitter, a quarter-wave plate, an imaging lens group, a line-array photosensitive chip, an image information processing module, and an image combining module, wherein the fiber laser, the fiber beam splitter, the fiber collimator and the laser beam expander are sequentially aligned to build an irradiating light path; a distal end of the irradiating light path falls onto an optical signal receiving end of the lithium niobate intensity modulator array; an optical signal sending end of the lithium niobate intensity modulator array, the polarization beam splitter and the quarter-wave plate are sequentially aligned to build a modulating light path, a distal end of the modulating light path falls onto a to-be-detected note; the to-be-detected note, the quarter-wave plate and the polarization beam splitter are sequentially aligned to build a reflecting light path, the reflecting light path is sent by the polarization beam splitter into the imaging lens group; the reflecting light path falls onto an optical signal receiving end of the line-array photosensitive chip via the imaging lens group; the waveform generator is connected to the signal amplifier, the signal amplifier is connected to the lithium niobate intensity modulator array; the image information processing module is connected to the line-array photosensitive chip, the image combining module and the waveform generator, and is configured to obtain a driving signal generated by the waveform generator and an electrical signal acquired by the line-array photosensitive chip, and rebuild a preliminary image of the to-be-detected note based on the driving signal and the electrical signal; and the image combining module is configured to combine a plurality of the preliminary images to obtain a high resolution image of the to-be-detected note; wherein the fiber laser is a wavelength-tunable fiber laser, and a laser light generated by the fiber laser comprises a red light, a green light and a blue light; wherein the preliminary image corresponds to the laser signal corresponding to the electrical signal, and comprises a red light acquired image corresponding to the red light, a green light acquired image corresponding to the green light and a blue light acquired image corresponding to the blue light; and the image combining module is configured to combine the red light acquired image, the green light acquired image and the blue light acquired image at a rate of 1:1:1 to generate the high resolution image of the to-be-detected note. a fiber laser, a fiber beam splitter, a fiber collimator, a laser beam expander, a lithium niobate intensity modulator array, a waveform generator, a signal amplifier, a polarization beam splitter, a quarter-wave plate, an imaging lens group, a line-array photosensitive chip, an image information processing module, and an image combining module, wherein the fiber laser, the fiber beam splitter, the fiber collimator and the laser beam expander are sequentially aligned to build an irradiating light path; a distal end of the irradiating light path falls onto an optical signal receiving end of the lithium niobate intensity modulator array; an optical signal sending end of the lithium niobate intensity modulator array, the polarization beam splitter and the quarter-wave plate are sequentially aligned to build a modulating light path, a distal end of the modulating light path falls onto a to-be-detected note; the to-be-detected note, the quarter-wave plate and the polarization beam splitter are sequentially aligned to build a reflecting light path, the reflecting light path is sent by the polarization beam splitter into the imaging lens group; the reflecting light path falls onto an optical signal receiving end of the line-array photosensitive chip via the imaging lens group; the waveform generator is connected to the signal amplifier, the signal amplifier is connected to the lithium niobate intensity modulator array; the image information processing module is connected to the line-array photosensitive chip, the image combining module and the waveform generator, and is configured to obtain a driving signal generated by the waveform generator and an electrical signal acquired by the line-array photosensitive chip, and rebuild a preliminary image of the to-be-detected note based on the driving signal and the electrical signal; and the image combining module is configured to combine a plurality of the preliminary images to obtain a high resolution image of the to-be-detected note; wherein the fiber laser is a wavelength-tunable fiber laser, and a laser light generated by the fiber laser comprises a red light, a green light and a blue light; wherein the preliminary image corresponds to the laser signal corresponding to the electrical signal, and comprises a red light acquired image corresponding to the red light, a green light acquired image corresponding to the green light and a blue light acquired image corresponding to the blue light; and the image combining module is configured to combine the red light acquired image, the green light acquired image and the blue light acquired image at a rate of 1:1:1 to generate the high resolution image of the to-be-detected note.