對於蘇聯外交政策的研究，基本上可以透過意識型態與國際關係理論兩種方式去解釋其行為。以二次世界大戰做分水嶺，筆者透過西班牙內戰（1936-1939）與國共內戰（1945-1949）兩場戰爭分析：一、兩場內戰前時代背景的差異及當時蘇聯國內領導者的思維。二、蘇聯援助中國共產黨和西班牙共和政府的目的。三、蘇聯對雙方提供的援助內容。四、歐美列強的態度對蘇聯援助政策的影響。五、蘇聯援助行動所獲致的成效及影響。六、綜合比較兩場戰爭蘇聯的行為模式。七、兩場戰爭後各自對國際情勢發展的影響。 　　筆者認為，藉由兩場內戰，可得出米爾海默（John Mearsheimer）的攻勢現實主義，最足以解釋蘇聯的國家行為。意識型態對於蘇聯的領導者而言只是包裝，其影響程度要讓步給蘇聯自身的國家利益。 / To study Soviet Union’s foreign policy, we can mainly use ideology and international relation theory to explain its behavior. World War II as a watershed, the author through the Spanish Civil War (1936-1939) and the Chinese Civil War (1945-1949) analyze: (1) Two different backgrounds of the wars and the thinking of the leader of the Soviet Union. (2) Why Soviet Union wanted to aid the Chinese Communist Party and the Spanish Republican government. (3) The aid provided by Soviet Union in two wars. (4) The attitude of other European powers towards Soviet Union’s policy. (5) Effectiveness and impact Soviet Union gained via the aid. (6) Analyzing and comparing Soviet Union’s patterns of behavior in these two wars. (7) Development of international relations after two war. 　The author believes that, by two civil wars, offensive realism which was maintained by John Mearsheimer, was the most adequate to explain the behavior of Soviet Union. For the leader of Soviet Union, ideology was package. It is the national interests that decides Soviet Union’s behavior.