Abstract: Objective This analysis was conducted to evaluate the current situation, present problems and influential factors in the reports of routine immunization coverage rate in Zhejiang Province. Methods Monitoring data of routine immunization surveyed from 2000 to 2004 were analyzed.Results The immunization coverage rates of five vaccines(BCG, OPV, DPT, MV, HBV) ranged from 98.71% to 99.65%, while the estimated rates ranged from 72.86% to 112.11% in 2000-2004, indicating significance with the reported rates. The different value(D) showed that the data of 2000 were unbelievable, the data in 2001, 2002 and 2004 doubtful and the data in 2003 reliable, main reason associated with the incompletion of EPI administration for floating children. Conclusion Evaluating the immunization rate from the population data on statistic yearbook issued by the higher level is not reliable.