The Paris school of scientific knowledge sociology, which is represented by laboratory study and actor-network theory, applies ethnographic methods to research and trace the micro process of scientific knowledge production and socialization for the first time. Ethnography advocates empirical data, analyzes material elements in the laboratory, investigates implied ideas in daily scientific activities and reconstructs scientific statements, which forms the constructivism principles of scientific knowledge, conforms to the trend of empirical turning and discipline integration in scientific and technological philosophy, and carries a certain implication for opening the black box of contemporary technology. However, it is worth noting that the dilemma of ethnography in the construction of scientific knowledge lies in its legitimacy, constructivism and motivation.