As a relational category, historical value has three elements. One is the objective attribute of historical phenomenon itself, and it is the material undertaker of historical value. Second, this objective attribute is the social subject, and the social subject is the winner or implementer of historical value. Subject and object always exist under certain time and space conditions. Therefore, the objective attribute of historical phenomenon and the organic connection between its object and environmental conditions become the third element of historical value. Historical value is the comprehensive unity of these three elements. No matter the object attribute, the subject condition or the relationship environment between subject and object changes, the historical value will change accordingly. Therefore, the definition of historical value can be expressed as: the objective attributes of historical phenomena act on certain objects and have a meaningful relationship under certain historical environment. Obviously, a simple and isolated historical phenomenon does not care about its value.