In clinic, magnetic resonance is one of the important ways to examine tumors, but not all tumors can be diagnosed by magnetic resonance. For intestinal tumors, respiratory tumors, etc., the diagnostic effect of magnetic resonance is relatively poor; for neurological tumors, some solid tumors, etc., the diagnostic effect of magnetic resonance is better. Magnetic resonance is able to distinguish the structural relationship of nerves, blood vessels, fibrous tissues, etc. in parenchymal organs in a more detailed way, but the resolution of cavity organs, such as lungs, stomach, intestines, etc., is relatively poor. In the clinic, magnetic resonance is mostly applied to tumor examination of parenchymal organs. Magnetic resonance can not only be used for tumor examination, but also has some significance in determining the benign and malignant nature of tumors. Magnetic resonance has a certain role in determining tumors with bone metastasis, brain metastasis, lymph node metastasis, etc. It can show the location of the lesion and outline the target area for radiation therapy if necessary. Although magnetic resonance has some discriminative value in determining the benign or malignant nature of tumors, professional pathological examination is still necessary to clarify the nature of tumors.