摘要：本文对机械院420实验室的液位控制系统进行了探讨。不使用其中的加热器、流量计等环节。集中精力研究液位控制过程，通过多次实验探寻比例、积分、微分各系数变化对液位控制品质的影响，实验结果和理论推想一致。本文结合实验数据阐述了比例、积分、微分各系数变化对液位控制品质的影响。在此基础上，最终确定的PID参数可以使液位稳定在29.8cm到30.2cm的范围（期望值为30cm）-Abstract: In this paper machinery 420 hospital laboratories in liquid level control system are discussed. Do not use these heaters, flow meters and so on. Concentrate on liquid level control process, through numerous experiments to explore the proportion, integral, differential changes in the coefficient of liquid level control quality of experimental results and theoretical consistency speculate. In this paper, experimental data on the proportion, integral, differential coefficient of the quality of liquid level control. On this basis, the final PID parameters can be determined so that a stable liquid level in the range of 29.8cm to 30.2cm (expectations for 30cm)