Data mining approach is used as a technique to obtain important information that can be used as supporting material in a decision . in this study, the association method is implemented to obtain relationship existing on population data , especially to get the relationship patterns of crime events related to characteristics of the population. In this case , invalid data and missing values must be handled carefully before building association rules. Apriori algorithm is applied to this method, since the algorithm is proven to generate rules with high degree of accuracy in establishing the pattern of connectivity between attributes . Association rules will be used as a basis for making policy related to the population problem .