This article analyzes and verifies the reliability of high repetition rate narrow pulse width multi-wavelength lasers. A block diagram method model of high repetition rate narrow pulse width multi-wavelength lasers was established, and reliability analysis of the laser was conducted at the initial design stage. The reliability results of each unit of the laser were quantitatively calculated, including failure rate λ and Mean Time Between Failures (MTBF), with an expected MTBF of the entire laser system being 1 798.8 hours. To meet the design requirements of the laser, reliability optimization of the laser was achieved through selecting high-quality crystals, first-level derating design of semiconductor lasers, and redundant design of power control. After optimization, the MTBF of the entire laser system was increased to 2 260.9 hours. The reliability optimization design results of the laser system were validated, and the validation results showed that the laser's MTBF could reach 2 400 hours.