The assessment of protection capability has become increasingly important with the rapid development of security systems. The assessment of protection capability is mainly composed of the definition of protection capability, the systems of evaluating indicators and assessment methods. In order to assess protection capability, the appropriate definition of it is the priority. Since there are a variety of protection capabilities in security systems which differ in different security systems, multidimensional definitions of protection capability can help to identify the protection capability in special systems more accurately. Then scientific systems of evaluating indicators should be established. The indicators of a certain protection capability differ in different conditions, thus it is necessary to establish systems of adaptive indicators, which may help evaluate the protection capability in certain security systems more exactly. Last, the accurate calculation of assessment should be taken into consideration. The study of quantitative calculation can help assess protection capability in security systems more accurately and gives guidance in the construction of security systems with the establishment of adaptive indicator systems in multidimensional protection capability because qualitative assessment can not fulfill the needs of the rapid development of security systems. The project studies a partial solution to the assessment of protection capability in security system and further meets the security industry's urgent needs for assessment of protection capability.