ObjectiveTo summarize the research progress of ultrasmall superparamagnetic iron oxide (USPIO) enhanced magnetic resonance imaging (MRI) in normal-sized lymph node metastasis of colorectal cancer.MethodThe relevant literatures published recently at domestic and abroad about USPIO enhanced MRI in normal-sized lymph node metastasis of colorectal cancer were collected and reviewed.ResultsUSPIO, a kind of lymph node targeted magnetic resonance contrast agent, could be used to evaluate lymph node metastasis of malignant tumors. USPIO enhanced MRI could detect normal-sized lymph node metastasis in colorectal cancer effectively compared with normal MRI. It provided a higher diagnostic performance than normal enhanced MRI. In addition, USPIO enhanced MRI could also distinguish inflammatory and metastatic lymph nodes better that were difficult to be distinguished by normal enhanced MRI.ConclusionUSPIO enhanced MRI shows a certain potential for clinical application in detecting normal-sized lymph node metastasis of colorectal cancer, but it has not been widely used in China.