通过对1995-2007年全国24个台站子夜均值数据的整理，总结出各类错误数据的特征，结合数据处理技术，利用Visual Basic语言编制了数据处理软件，建立一种自动化的错误数据识别方法，为数据整理和处理分析提供高效率的工具。为今后子夜均值数据的正确判断提供一个方便快捷的途径。

Based on the analysis of geomagnetic absolute averages at local midnight from 1995 to 2007 of 24 geomagnetic observatories in china, we summarized several characteristics of wrong data. In order to identify the wrong data efficiently and automatically, we designed the data processing software through Visual Basic and provided a correct approach to identify wrong data.