In recent years, security firms have been growing rapidly in Taiwan. There are over 500 security firms existed, but not all of them have sound management and efficient services. Up to now, there is still no effective evaluation model for customers to select suitable security firms. Under this circumstance of rapid growth, security firms also expect the appearance of reasonable evaluation criteria in the security industry for them to follow. The objective of this study is to establish the objective evaluation criteria of security firms and measure their weights so as to assist customers to use these criteria that are more objective in the selection of security firms. This study constructs the evaluation hierarchal of six dimensions and twenty-seven criteria through literature review and interviews with experts, and calculates the weights of evaluation dimensions and criteria by fuzzy linguistic preference relation approach (FLPR) form related experts judgments.