The Dual Band Laser Evidence Discoverer can perform non-destructive detection of on-site biological traces, directly obtaining the most primitive and authentic information without damaging biological active substances (DNA). It has a direct detection function for sweat fingerprints, dust fingerprints, occult blood fingerprints, and oil fingerprints, providing conditions for the on-site discovery of biological evidence such as hair, bones, clothing fibers, semen, urine, human body fluids, and shed cells.