The paper takes the northeast seismic zone as an example and analyzes the completeness of the small earthquake catalogues in terms of the Gutenberg-Richter magnitude-frequency relation. The magnitude lower limit is determined in different periods and in different areas by using the quantitative analysis methods. In addition, b value and average annual incidence of earthquake in northeast seismic region are obtained with the use of mathematical statistics method. The effects of the integrated data on the seismicity parameters and seismic hazard analysis are also discussed. It is shown that the completeness analysis provides a possible means for obtaining more accurate seismicity parameter and shows better performance in representing actual regional seismicity level for areas of low seismicity. The researching methods of this article and its conclusion can be used as analysis on integrity of earthquake data and seismic activity research reference.[著者文摘]