For the application of automatic biochemical analyzer in liquid level detection module, automatic biochemical analyzer requires high accuracy of liquid level detection in medical industry. However, the current domestic research and development of liquid level detection module can not meet the requirements of users for a long time. But after long-term efforts of our engineers, we finally overcome the related problems. The liquid level detection module PCS0902 of our company has realized the plasma stratification detection after centrifugal separation on the user equipment.