作為海島型態的臺灣，對外交通十分仰賴港口。在日本統治臺灣後，安平與基隆、淡水、打狗（高雄）被指定為「條約港」，提供各國貿易通商。同時，由於港灣本身的地理條件與外在因素，導致部分港口沒落而喪失原本的地位。在日治之後，高雄與基隆分別取代安平與淡水，成為臺灣南北最大的港埠都市。即便如此，臺南地區仍然以安平港作為貿易進出之門戶，惟安平港在自然水文環境的影響下不斷淤積，導致航道改變、商業受阻，促使政府及民間投入港口改良及新闢運河的行動。 本文以安平港為研究中心，利用臺灣總督府公文類纂，以及臺灣總督府的港灣調查資料，並佐以報紙資料，分析明治、大正年間安平港興衰的過程。本文重點有三：(1)討論日治前期安平港地位及其航運價值的變遷。(2)討論疏浚政策對安平港的影響，以及地方團體的參與與訴求作一探討。(3)河川與港口，安平港航道屢屢因鹽水溪與曾文溪氾濫而淤積，隨著在大正初年進行詳細的河川調查作業，以及日後擴大調查範圍，討論在河川政策的明顯轉變之下對安平港的影響。(4)港口與運河，討論新、舊臺南運河對安平港的助益。

Surrounded by the Pacific Ocean, harbors in Taiwan are the main contact windows with the world outside. During the period of Japanese colonial rule, the Anping Harbor, like the Keelung, Danshui and Kaohsiung Harbors, was appointed as the treaty port for worldwide trade. However, due to geography and outer factors, the Kaohsiung and Keelung Harbors replaced respectively the Anping and Danshui Harbor as the biggest Southern and Northern harbor cities in Taiwan. Even though it was no longer the biggest harbor of Southern Taiwan, the Anping Harbor was still regarded as the contact window for trade in the Tainan area. However, in addition to being silted up naturally from time to time by the riverside where it is situated the Anping Harbor also faced as a consequence with changes of shipping channels and business setbacks. All these caused the government and local people to improve the shipping and to construct a new harbor. Centered on the Anping Harbor materials, in addition to the official document of Taiwan government, the harbor investigation of Taiwan government as well as newspaper documents, the thesis is aimed at outlining the fifty year history of the Anping Harbor's rise and decline in the early Japanese colonial rule during the Meiji and Taishou period. In summary, there are four points in this thesis: 1. A discussion of the navigation value of the Anping Harbor and the change of its place in early Japanese colonial days. 2. A discussion of the influence of government harbor dredging policy on the Anping Harbor and the local group's petition. 3. River and harbor. The river course of the Anping Harbor was flooded being repeatedly by Yan-shui and Tseng-wen Rivers. Beginning with river investigation during the early period of Shouwa, there had been a remarkable change of the river policy. What was the impact on the Anping Harbor under this change? 4. Harbor and shipping canals. This involves a discussion of the influence of old and new Tainan shipping canal on the Anping Harbor.