This article deals with the relationship between official immigrant villages and the irrigation development in Eastern Taiwan. The irrigation development in Eastern Taiwan began its obvious progress in both the ideas and technologies of irrigation in 1910s, after the sett1ement of official immigrant villages. The Governor General of Taiwan established and improved many water conservancy institutions such as Yusino irrigation ditches、Toyota irrigation ditches、Hayasida irrigation ditches and Pei-nan irrigation ditches for the sake of Japanese agricultural immigrating business and the advancement of rice implantation. Its modern technologies and the irrigation networks had profound influence up till nowadays.