Crime occurrence is one of the most significant problems in Zanjan city which is considered as a challenging problem for police in this city and it threatens the safe life of citizens of this city. This paper aimed at geographical analyzing of crime in Zanjan city using Geographical Information Systems (GIS). Street assaults have been selected as the case study of this paper. This article is based on descriptive and analytic methods and the spatial patterns of crime in this city have been identified through some statistical methods including: Mean Center, Standard Deviation Ellipse, Nearest Neighborhood Index and Quartic Kernel Density. All the street assaults which are occurred in Zanjan city during a year have been collected in this article using police records. The results of this study show that according to Nearest Neighborhood Index (NNI), spatial distributions of street assaults in Zanjan city are significantly clustered which suggests the existence of hot spots and cool spots in the city area. The most appropriate method for visualizing crime data as a continuous surface is Quartic Kernel Density Estimation. Based on this method, the major street assault hot spots have been identified in Sadi Street, Amir Kabir Street and Hafte Tir terminal and also Central Business District (CBD) of this city.In order to improving security and reducing crime rate in the areas of concentrated crime, some suggestions which should be considered as a priority for people in charge of urban management, have been indicated in this article.