As the name implies, fast paraffin wax focuses on “fast”, so is it only fast that its accuracy is greatly compromised? No, it is not. Fast paraffin is based on accuracy, unlike rapid frozen sectioning in surgery, which is time-critical, urgent, non-dehydrated and thick, and has a certain rate of misdiagnosis. At present, most of them adopt ultrasonic technology, which makes the tissue processing fluid make shrinkage movement under high-frequency resonance of 800,000 times/second, so that the tissue processing is more adequate and the section quality is no less than traditional paraffin section or even clearer and more transparent, so that the work which takes days is completed within 1 hour. Rapid paraffin is most suitable for some small specimens: such as small tissues from gastroscopy, colonoscopy, bronchoscopy, oral cavity, nose, pharynx, cervix, epidermis, etc.; small tissues obtained from liver, lung, pancreas and other organs by percutaneous puncture under the guidance of ultrasound, CT or X-ray; tissues from body surface tumors, lymph nodes, prostate, breast, etc. by direct percutaneous puncture; small tissues taken under thoracoscopy, laparoscopy, hysteroscopy, etc. Once the lesion is found, a clear pathological diagnosis is obtained as soon as possible, which not only relieves the anxiety and impatience of patients and their families, but also, more importantly, wins valuable time for clinical treatment. Large specimens can also be done fast paraffin, but it is not recommended, when more blocks need to be taken, which will inevitably cause unnecessary chaos, generally speaking, the larger the tissue block, the lower the quality of the section, the more routine pathology can be done at this time, fast paraffin seems unnecessary, and each case of fast pathology is a test or challenge to the pathologist’s emergency ability, technical ability, and pathologists are in the toxic conditions containing benzene, formaldehyde, acetone, etc. The economic benefits are not very cost-effective compared with conventional pathology, but specifically for each patient waiting for urgent treatment, rapid paraffin pathology diagnosis does have important significance.