This paper reports the method of the displaying fingerprints, by exciting fluorescence with laser. The experiments have demonstrated this way being more superior to the normal method. In the fingermarks, left on the surface of objects, there are very small amount of aminoacid containning in the sweat. when they are painted some materials consisting of fluorescent substance leave on the marks, it may form a compound with the aminoacid. Therefore visible fluorescent light will be excited by a laser with certain wave-length. A picture of the fingerprint-particularly for those cannot be shown by normal method is displayed. In our experiments, Samples of one kind are more over four hundred fingerprints with appropriate pressure less perspiration, and gathered on white paper. The results show that the sum of clear and perfect fingerprints inspected by this way, is 2. 3 times of that observed by normal method (see Table I and II). Samples of another kind are the fingermarks remained on the surface of less smooth, hard and black plastics. It is almost impossible to take photographs of theese samples by normal method. By using our method, the clear picture of fingerprint can not merely be seen but also may take nice photographs of them. This have been successfully applied to investigate facts. Thus, the method of displaying fingerprint with fluorescence excited by laser is superior to the normal method. In these experiments, we have used the source of Ar+ laser with wave-length 514. 5nm and 488. 0 nm. In observing the photographs, we use an adequate filter for decreasing the strong background laser and rejecting the interference of fluorescent light from the fingerprints carrier.