清嘉慶、道光年間，統治急速衰敗，經濟、社會問題叢生，士林風氣轉變，開始掙脫繁瑣考據的漢學和空談性理的宋學，轉向經世致用。魏源一生跨越了鴉片戰爭這一時代的分水嶺，他是中國社會由傳統的古代走向近代的轉折時期，經世派重要的代表人物之一，他開啟了認識世界的時代風氣。本文試由其家世與思想個性、學風與政風，漕務、鹽務和河務、水利、貨幣金融與對外貿易、夷務與海防等方面，來論述他經世思想形成的背景與內容，了解他在鴉片戰前的經世主張及其經世事業的成就，和鴉片戰爭爆發，戰後面對這亙古未有之變局他如何與時並進，將經世致用的精神高度發揮，進而提出「師夷長技以制夷」的劃時代主張，並開啟了中國近代化改革時政的大方向。本篇之完成，除讓人對魏源之經世思想有更清楚的了解外，並能扭轉部分國內外學者對清季自強運動興起之動力，認為幾乎是純受外力之衝擊所引起之見解，如鄧嗣禹與費正清(John K. Fairbank)教授等所謂西力衝擊說曾經盛極一時，且進一步證明中國傳統的經世思想，亦為自強運動興起的動力之一。

In the course of Chia-ch'ing and Tao-kuang, the dominion decayed rapidly. Economic and social problems tufted around the regions. Consciously, academicism converted, from slipping the Study of Han Dynasty's inextricable textual research and Sung's idealistic philosophy toward statecraft practice. Wei Yuan, striding across the span of opium war divide in his whole life, he contemporarily stood on the turn point through China traditional ancient society to recent age, also became one of the important representatives of the statecraft sect. He surely unsealed the climate of acquainting the world. This thesis is trying to discuss with the background and content of Wei Yuan's theory of statecraft, basing on the different ways that forming his own statecraft thought, such as his personal characteristics like his birth﹑thought; the style of study as well as politic discipline; also in the aspects of the business that he used to be involved, the affairs of transporting grain by water﹑selling salt﹑water management and conservancy; currency﹑finance﹑and external trade; immigrant and coast defenses etc. , so that we can figure out what makes his achievement concerning his appeal and career of statecraft before the opium war as well as how to develop the spirit of statecraft to the highlight after the war bursting out that he had to face on the unprecedented changes, while he approached simultaneously. As a result, he alleged an epochal opinion-”learning the skill of invaders and take over them by it” in response to that changes, further unlock the great direction of China modernizing, reforming the decayed situation. With the reference of this thesis, we are not only able to get the picture of Wei Yuan's theory of statecraft more clearly than before, but also can strongly reversed the inaccurate notion of part of the foreign and local scholars had, that the motive of the Self-strengthening Movement in late Ch'ing China was simply reflected by the impact of external force, for example, the saying of “Western impaction” claimed by several professors such as Ssu-yu Teng and John K. Fairbank, was popular for a while. This thesis farther approve that the China's traditional theory of statecraft is one of the motives of the Self-strengthening Movement emerging in late Ch'ing China as well.