This paper introduces the measuring principle of the typical measuring devices of the water level in the drum of the boiler in heat power plant, and analyses the errors of different measuring methods. Several solutions offsetting errors are put forward. 介绍火力发电厂锅炉汽包水位典型测量装置的测量原理,并对各种测量产生的误差进行了分析,提出了消除误差的方法与措施。