Road accident hotspots Identification is important in road safety improvement project, especially in aspect of effective funds allotment. This paper presents a simple methodology called dynamic step filtration method to study the spatial patterns of accidents in a highway or a highway network. The dynamic step filtration analysis is improved from average and steady step filtration method, basing on the character that the accidents happened in random unit length along a highway can be calculated accurately. The intersections can be disposed as safety influence distance and the highways of all levels can be translated to same criterions, so the dynamic filtration analysis can be used in a highway network. This paper shows the theory and application process of DSFM. The application of this methodology is illustrated by a example. All methods are used in a highway, and dynamic step method is the best through contrastive analysis. The application in highway network identifies two segments with more accidents.