Human being can be exposed to various blue light in daily life and workplace. The biological effects and biosafety of blue light have attracted more and more attentions in recent years. A series of guidelines, technical reports and standards have been issued at home and abroad on the potential health hazards of blue light, the biological safety assessment of blue light and the risk group of blue light products. The “blue light hazard” is a technical term used in the standard system for the photobiological safety assessment of lights and lamp systems. The term does not generically imply that blue light radiation is risky nor should it be mistakenly considered as harmful. Blue light plays an important role in maintaining normal vision and human health. Rational understanding of blue light hazard would have positive effects on the development and application of blue light technology. This article focuses on some important properties and sources of blue light radiation, biological effects of blue light and the assessment system of blue light biosafety, and intends to make an objective and rational analysis of the current consensus and misunderstanding on the blue light hazard, and reviews the relevant standards on the biosafety of blue light radiation and the evaluation methods of blue light biosafety.