As the plastic industry rapidly develops, the resultant pollution from microplastics (MPs) and nanoplastics (NPs) has become widespread, significantly affecting human health and the ecological environment by their transmission and enrichment in the food chain. This article reviews an effective technique used for analysing the toxicological and metabolic mechanisms of MPs and NPs within organisms, namely the fluorescent tracing technology. This technology facilitates the qualitative and quantitative detection of MPs and NPs within organisms, enabling the monitoring of the behaviour and effect of MPs and NPs within biological systems. The paper explores the principles, advantages and disadvantages of various currently employed fluorescent tracers; summarises the equipment and technology currently utilised for MPs and NPs detection and tracing within organisms and discusses the application of the technology in studying MPs and NPs effects on organisms. Finally, it prospects the application prospect of in vivo fluorescence tracer technology for the detection of MPs and NPs, and points out the limitations and development directions of this method in subsequent research.