分析了电站锅炉并联管组单相流体流量偏差计算的现有标准方法存在计算误差的原因．通过建立更接近真实的物理模型，研究了Ｚ型集箱连接系统单相流体的流动特性，获得了理论解．实例对比计算表明，实际流量偏差越大，现有标准方法产生的计算误差越大．本文的工作为准确计算Ｚ型集箱连接系统单相流体流量偏差，提供了一种有效的方法． The reasons for the calculation errors of the existing standard methods for calculating the single-phase fluid flow rate deviation in the boiler-parallel unit of power plant are analyzed. By establishing a more realistic physical model, the flow characteristics of a single-phase fluid in a Z-box header system are studied and a theoretical solution is obtained. The comparative calculation of examples shows that the larger the actual flow deviation, the larger the calculation error produced by the existing standard methods. The work in this paper provides an effective method to accurately calculate the single-phase fluid flow deviation in the Z-box header system.