 Methods: The investigators carry out a cross-sectional survey among children aged 0 to14 years across Kashgar area in China. The participants are selected by a two-stage and clustered random sampling method. Participants are asked to undergo urinary tract ultrasonographic examinations, provided blood and urine samples to analyze. Their parents or guardians are asked to fill out the questionnaires. Children those who are found with any abnormalities of their urinary system by ulrtasonography will undergo a low-dose computed tomography CT to confirm the abnormalities. The end point of this study is to calculate the prevalence rate, distribution and associated factors of pediatric urolithiasis in Kashi area. 