Abstract: An in-situ detection system involving multi measurements coupling with a nucleation reactor includes a crystal nucleus transient evolution imaging system and a time-resolved detection system which are in-situ connected with a rotating micro-liquid film reactor. A micro negative pressure sampler is made to capture nucleation particles in high-speed shear field and enter the visible observation area. The sampler is in-situ connected with a high-speed camera and microscope objective to obtain instantaneous images of the nucleation process at the nanoscale and in-situ capture the transient evolution behavior of crystal nuclei. The sampler is used for capturing nucleation particles in a high-speed shear field, and is connected to a flow-through cell.