Abstract: The fracture distribution in formation in vertical direction plays an important role in petroleum engineering. However, the imaging logging which reveals the fracture distribution precisely can not be wildly used due to its highly cost. Therefore, it is very meaningful to establish a model which can analyze the fracture distribution based on conventional logging data. By combining fuzzy mathematics with conventional logging parameters which have response to the existence of fractures in formation, a novel calculation model of the fracture index has been established. Comparing the calculation result of established model with field imagining logging data, it is found that the new model can reveal the formation fracture distribution accurately. The Field application results indicated that the new model is a simple but very effective model to analyze the fracture distribution in formation.