Pathological section examination is a way and method to diagnose diseases, mainly for the specimens cut in surgery, specimens clamped in lumpectomy or tissues and cells obtained by fine needle puncture, which will be made into pathological sections, and the morphological changes, a morphological discipline given by pathologists under light microscopy for diagnosis. Diagnostic pathological section examination is mainly reflected in the following aspects: i. To present a clear pathological diagnosis of clinically relevant diseases. Second, it can provide reliable etiological evidence or clues. Third, it can provide relevant prognostic factors. Fourth, pathological examination is a special form of consultation for certain diseases. V. The pathological examination request form is an invitation for consultation issued by the clinician to the pathologist. In conclusion, pathological section examination is a gold standard for disease diagnosis and a very necessary form of examination.