本文以糧食貿易網絡為中心，重新評估外在部門在兩次世界大戰之間 (1918-1936) 中國經濟之角色。過去的研究為此曾經進行辯論，並以雙互之競爭為題而把中外商業關係加以二分化。本文試圖透過重建中國糧食市場（主要是米穀、小麥及麵粉）之國內、國外貿易網絡，以展示和釐清兩者之間複雜的關係。本文亦在通商口岸的層次探討兩者的關係。本文亦審視在此一時期米與麵粉進口變動之關聯，以更深入分析中國各通商口岸本、外地糧食進口趨勢背後的原因。 如本文所示，在兩次世界大戰之間的中國經濟充滿複雜的關係。對主要糧食之研究說明，一種糧食的貿易表現並不單單取決於它的外來對手，同時亦受到國內市場其他因素的影響，並取決於該市場的經濟規模。較大的市場以其本身之規模，更容易吸引競爭。可是，競爭並不單單是外來的，其他可替代的糧食作物亦可構成相當的競爭。此外，「中外經濟競爭分析」忽略中國糧食貿易網絡的本質。如本文所示，海外華人把米穀輸入中國，顯示中國商業網絡的擴展，而中國的麵粉工廠廠主又以進口外來小麥，以與外來麵粉一較高下。簡單來說，「中國與世界」的二分法未能提供一個令人滿意的分析架構，未來的研究宜放棄這個架構，以追求瞭解其他在近代中國經濟與社會的根本變化。

This paper uses the case of grain trade networks to re-assess the role of the foreign sector in China’s economy in the interwar years (1918-1936). Previous studies have debated over the issue and mainly dichotomize the Sino-foreign business relationship in terms of competition. This paper attempts to explore the complex relationship between the two by reconstructing both the domestic and foreign trade networks in the China grain market (mainly rice and paddy, wheat and flour). It also examines the relationship between foreign and domestic grains at the trading port level. To further explore the factors affecting the movements of both domestic and foreign grain imports into Chinese ports, this paper also examines the relationship between the movements of rice and flour during the period under review. Our analysis demonstrates that China’s economy in the interwar years was full of complex relationships between different sectors. The case of principal food grains has illustrated that the performance of one kind of grains was not simply determined by its foreign rivals. It was also affected by other sectors of the domestic market and depended remarkably on the scale of that market. Larger markets, by virtue of their size, seem to attract competition more easily than smaller ones. Yet, competition might come not just from foreign rivals; domestic ones, including those of different kinds but substitutable, should be of no lesser importance. Besides, the “competition analysis” fails to recognize the very nature of the China grain trade networks. As this paper has shown, overseas Chinese imported rice and paddy into the country, showing an extension of Chinese business networks, while Chinese flour-mill owners used foreign wheat imports to compete with foreign flour. In short, the dichotomy between “China and the world” simply fails to provide a satisfactory analytical framework. Further research would benefit from leaving this framework for other fundamental changes in modern Chinese economy and society.