This report presents the analysis of the optical method development of flow investigation since the invention of lasers in 1960. The history of the first laser development and the contribution of national and foreign scientists to quantum electronics are described. New optical methods of flow investigation were proposed due to high quality of laser radiation: high intensity density, high temporal coherence (monochromaticity), spatial coherence (small divergence), polarization degree. The historical analysis is based on the original and review articles that were published due to the 50th anniversary of laser invention and analysis of the Proceedings of «Optical methods of flow investigation» conference in 1991 – 2009.