There are a number of changes taking place in international relations theory. Many academics contend that only through synthesizing existing theories can IR theory meet the challenges of the real world, but they ignore the internal logic of theoretical evolution. Synthesis of IR theory has restrictions, and only through improving the explanatory power by theoretical integration while maintaining consistency can synthesis be successful.  The author uses the analytical perspective of philosophy of science to explore and analyze the conditionality of IR theory integration, and on a foundation of history and logic attempts to offer an answer to this question.