Abstract: Abstract: Paraffin section is not only the main experimental methods of histology, developmental biology studies, but also an important tool of observing the pathological changes in pathology. It’s widely used in clinical pathology, teaching and research work. However, during the proceeding, there always arise such problems as section fragmentation, section off, uneven staining, blur and unconspicuous cell structure’s staining result, etc., owing to many experimenters haven’t been trained rigorously and systemically, they are lack of experience and may apply improper operation. Based on my reading of a lot of paraffin section’s relevant literature, combined with my own experience, I summarized the key influence factors of sections quality as follows: selection of experimental reagent, time and temperature. I analysed the three key factors’ impact and potential problems that may occur in each experimental steps, and details how to control them to improve the quality of section.