汽包水位是自然循环汽包锅炉运行中的一个重要的监控参数，它不仅反映了锅炉蒸汽量与给水量的质量平衡关系，也反映了各种能量在有限容积中的平衡关系。本文通过对汽包水位变动计算式的分析，探讨了主要干扰作用下水位的变化规律，归纳总结出水位的瞬间变化方向取决于扰动因素如何影响蒸发区工质的平均比焓，变化幅度取决于其改变能力的大小，水位变化的最终趋势取决于汽包工质质量收支，并通过这个汽包水位变动计算式对现场事故中的水位变化进行了分析。Steam drum water level is an important parameter to monitor of a natural circulation drum boiler, it not only reflects the boiler steam and water quality balance, also reflects a variety of energy in a finite volume balance relationships.This article through to the steam drum water level changing calculation type analysis, discussed the main disturbance level changes, summed up water level change direction depending on the perturbation factors how to influence the evaporation zone of average specific enthalpy, changes in amplitude depends on its ability to change size, the change of water level the final trend depends on the drum quality of balance of payments, and through the steam drum water level changing calculation on accident of water level variation are analyzed.