Since its inception, laser technology has undergone a leapfrog development from fundamental exploration to extensive clinical applications. In its early stages, lasers were mainly used for simple tissue cutting. With continuous technological innovation, their clinical value in precision therapy and minimally invasive intervention has become increasingly prominent. Lasers have evolved into an indispensable tool for the treatment of numerous diseases, driving a paradigm shift in diagnosis and treatment within the medical field. Lasers of different wavelengths exhibit significant differences in penetration depth and absorption characteristics within biological tissues. This wavelength selectivity enables lasers to act precisely on target tissues while minimizing damage to surrounding normal tissues. For instance, specific wavelengths can be selectively absorbed by chromophores such as melanin and hemoglobin, thereby achieving precise treatment of related diseases. This constitutes the fundamental mechanism underlying the precision of medical lasers. This review aims to systematically summarize recent advances in the working principles, expanded clinical applications, and cutting-edge research trends of various wavelengths of lasers in medicine. It is intended to provide comprehensive and up-to-date references for researchers and clinicians in related fields, and to promote the further development and application of medical laser technology.