Objective To analyze the examination results of external quality assessment (EQA),at all levels of iodine deficiency disorders (IDD) network laboratories in Ningxia Province and to further standardize and improve the laboratory,and to provide a reliable laboratoryquality assurance for surveillance and control of IDD.Methods The examination results of EQA at all levels of IDD laboratories in Ningxia Province were statistically analyzed in accordance with the National Reference Laboratory (NRL) of IDD (2002-2011).Results Laboratory hardware equipment and technology at all levels met the testing requirements,and qualified rate of quality control increased year by year.Both of the response rate and qualification rate of urineiodinelaboratories at provincial level were 100% in the past decade.From 2005 on,the response rate of city laboratories had been 100%,and the qualification rate had been 100% since 2007.The response rate and qualification rate of saltiodinelaboratories at both the provincial level and the city level were 100% in the past decade.The response rate of saltiodinelaboratories at county level had been 100% since 2004,and the qualification rate had been 100% since 2009.Saltiodine and urinary iodine levels were fully qualified for the past three years at provincial,municipal and county levels.Conclusions All levels of IDD network laboratory in Ningxia Province runs good,EQA is fully qualified,and is able to provide a reliable laboratoryquality assurance for surveillance and control of IDD.