Abstract: Objective The present study was designed to gain insight into the problems and solutions for the improvement of the accuracy of filling in underlying causes of death，exactly quantifying the proportion of deaths，and determining the severe diseases which should be prevented and controlled principally，providing basis for the establishment of the strategies for their control and prevention．Methods Data of the dead cases reported by Centers for Disease Control and Prevention at district or county level in Taiyuan City was cleaned and taken statistical analysis after the database was created with MicroAccess．Results Of the 5554 dead cases reported in 2005，the accuracy rate and the error rate of the filling-in of underlying causes of death were 74.97％ and 25.03％，respectively．Among these false items，the proportion of symptoms or signs was 47.08％，the highest．Various failures were in the second place with the proportion of 31.97％．There were two main reasons for the mistakes in filling in underlying causes of death：some doctors did not clearly understand the conception of underlying causes of death，and filling-in of multiple causes of death in Medical Certificates of Death did not observe the standard procedures．Surveillance data in 2006 showed that the accuracy rate of filling in the multiple causes of death increased from 64.26％ to 70.98％ and the accuracy rate of the filling of underlying causes of death from 74.50％ tO 82.44％ after training．Conclusion The accurate judgment of underlying causes in death surveillance is a key factor affecting the surveillance quality．By exploring effective management mode of the surveillance system for cause of death and strengthening the construction of capacity of talented persons engaged in the surveillance on cause of death，the problems on inaccurate judgment of underlying causes of death may be resolved and healthy development of the surveillance system for cause of death Can be achieved．