1. A fingerprint identification method, comprising: placing a finger on a photoelectronic sensor module; emitting an invisible light beam toward the finger by a first light emitting element and emitting a visible light beam toward the finger by a second light emitting element; reflecting the invisible light beam to the photoelectronic sensor module after the invisible light beam passes through the finger, such that the photoelectronic sensor module receives at least one invisible light intensity signal of the invisible light beam, and reflecting the visible light beam to the photoelectronic sensor module via a surface of the finger, such that the photoelectronic sensor module receives at least one visible light intensity signal of the visible light beam; generating at least one invisible light photocurrent signal based on the invisible light intensity signal by the photoelectronic sensor module, generating at least one visible light photocurrent signal based on the visible light intensity signal by the photoelectronic sensor module, and transmitting the invisible light photocurrent signal and the visible light photocurrent signal respectively to an analog/digital converter module by the photoelectronic sensor module; generating at least one first digital signal based on the invisible light photocurrent signal by the analog/digital converter module, generating at least one second digital signal based on the visible light photocurrent signal by the analog/digital converter module, and transmitting the first digital signal and the second digital signal respectively to a processor module by the analog/digital converter module; and generating a gray-scale fingerprint image based on the first digital signal by the processor module, generating a colored fingerprint image based on the second digital signal by the processor module, and performing identification based on the gray-scale fingerprint image and the colored fingerprint image, wherein the processor module comprises an analyzing program, a converting program and a validating program, and the step of performing identification based on the colored fingerprint image further comprises: executing the analyzing program to analyze the colored fingerprint image with a first color model, thereby obtaining first chromaticity coordinates corresponding to the colored fingerprint image; executing the converting program to convert the first chromaticity coordinates into second chromaticity coordinates with a second color model; executing the validating program and comparing whether the second chromaticity coordinates meet a predetermined second skin color threshold; determining that a finger print of the finger is a real fingerprint if the second chromaticity coordinates meet the second skin color threshold; and determining that a finger print of the finger is a forged fingerprint if the second chromaticity coordinates do not meet the second skin color threshold; wherein the step of analyzing the colored fingerprint image with the first color model further comprises: setting the first color model to be an RGB color model; obtaining the corresponding first chromaticity coordinates based on the RGB color model, obtaining a red wavelength curve, a green wavelength curve and a blue wavelength curve based on the first chromaticity coordinates; determining whether the red wavelength curve overlaps the green wavelength curve and the blue wavelength curve; and executing the converting program if the red wavelength curve does not overlap the green wavelength curve and the blue wavelength curve.