Abstract: Objective To investigate the extra value of 99TcmO4- planar imaging combined SPECT/CT tomography imaging in the diagnosis of ectopic gastric mucosa. Methods 99TcmO4- planar imaging and 99TcmO4- planar imaging combined SPECT/CT tomography imaging were performed separately on 33 and 26 children suspected ectopic gastric mucosa. The extra value of SPECT/CT tomography imaging was evaluated in the diagnosis of ectopic gastric mucosa by referring to clinical result. Results In all 59 cases, the sensitivity, specificity and accuracy rate of 99TcmO4- planar imaging vs 99TcmO4- planar imaging combined SPECT/CT tomography imaging in the diagnosis of ectopic gastric mucosa are 66.67%, 33.33%, 54.55% vs 85.71%, 91.67%, 88.46% respectively. The specificity and accuracy rate between the two groups were significantly different while sensitivity was not statistically significant. Conclusion The 99TcmO4- planar imaging combined SPECT/CT tomography imaging may improve the specificity and accuracy in the diagnosis of ectopic gastric mucosa and reduce unnecessary surgical treatment.