In recent years,the road transportation volume of HAZMAT ranges from 0.1 billion tons to 0.2 billion tons annually in China [1]. With the increase of the HAZMAT freight amount, there were the hazmat road transportation accidents frequently, which caused great damage to the national economy, peoples’ life property and the environment resources. Because of the physic-chemical characters of HAZMAT (such as explosion, combustion, poison, corrosion, combustion supporting), a more serious secondary accident is often derived from the former accident which poses a great threat to pedestrians, residents, ecological environment, buildings and vehicles. It is significant to seek a mathematic model for estimating the accident handling time. Only in this way, can the traffic situation be controlled timely. Also, according to the estimate of the accidents handling time, once an accident happened, an emergency response plan can be formulated appropriately. The following scholars have studied the causes and the consequences of the accident. A. Ronza [2] used transportation accident databases to investigate ignition and explosion probabilities of flammable spills by event trees; C. Samuel [3] presented a temporal trend study of HAZMAT incidents occurring through the transportation of flammable liquids; Bahareh Inanloo [4] weighed exposure health risks, proximity to vulnerable areas, delay costs and trucking expenses of HAZMAT cargo routing by Python programming. Although there has been many studies on road transportation accidents of HAZMAT, the disposal of these accidents was always neglected. Moreover, with the advantage of causal analysis, Bayesian network is widely used in the case study of accidents in transporting hazardous meterials. L.J. Zhao [5], developed a Bayesian network of 8 nodes(road condition, weather, management, human, HAZMAT packing and loading, transportation vehicle) which based on a database of 94 cases transportation accidents of HAZMAT. T. Zhu et al [1]. studied 162 accidents that occurred during the transportation of HAZMAT and concluded that the following major factors were responsible for the accidents: such as road condition, weather, management, human, HAZMAT packing and loading, transportation vehicle, the number of deaths and the number of injured. X. Wang [6] concluded the following factors: human, type of tank, weather, road condition. However, the related research was mainly to analyze the cause of the accident, the vital factors such as handling time, type of the former accident and the secondary accident were always neglected. In this respect, 902 transportation accidents of HAZMAT were studied from the beginning of 2013 to 2016 in this paper. A new BN was developed for estimating accident handling time and assessing the difficulty of each types of accidents.