Owing to the unique physical, chemical, optical, and biological properties, plasmonic nanoparticles (PNPs) have been widely used in various research fields such as materials science, biology, and medicine. The optical properties of PNPs can be regulated by changing their composition, shape, and size, so that a suitable light-scattering probe can be screened by means of controllable synthesis. Real-time study of the dynamic behavior of PNPs at the single molecule level is of great significance for understanding the biological behaviors of living cells and tissues, fabricating functional nanomaterials, and developing new chemical biosensors. Starting from the traditional dark-field microscopy (DFM), we have developed a series of plasmonic light-scattering imaging techniques with high sensitivity, high temporal-spatial resolution, and high throughput through optimizing the assembly of light sources, detectors, and other optical components, and applied these techniques to single molecule detection, multi-particle sensing, single cell imaging, biological process tracing, and so on. Based on the PNPs with optical anisotropy, we have also developed a three-dimensional scanning imaging system for living cells and asupercontinuum laser light-sheet imaging system coupled with high-speed capillary electrophoresis system, advancing the study of single molecule spectroscopy. This paper will summarize the work on PNP single particle analysis and imaging in our research group during the past ten years, and put forward some new ideas for further development in this field.