Hydroxyl (OH) is a widely existing product in the combustion reaction process. In combustion diagnosis technology, the two-dimensional spatial distribution based on hydroxyl is commonly used to characterize the structure of the flame front. Hydroxyl is an important parameter in characterizing the flame temperature, flame surface density, and heat release rate. The effective detection of hydroxyl in combustion flame is an important support for exploring the evolution of combustion dynamics and revealing the mechanism of random flame events. Planar laser-induced fluorescence (PLIF) has several advantages as an optical measurement method: high spatial and temporal resolution, non-intrusiveness, and component selection. PLIF has successfully observed the structure of various combustion flames, such as Bunsen burner flame, turbulent flame, swirl flame, and supersonic flame, which provides an important reference for establishing combustion models. This paper starts with the basic principle of PLIF detection, followed by the development history and research status of PLIF technology in the field of combustion diagnosis. Then, it introduces the PLIF ultraviolet light source technology based on dye laser, optical parametric oscillation, and Ti:sapphire tripling-frequency, and discusses the characteristics of different technical routes. Finally, it prospects the development of UV laser technology for OH-PLIF.