Preliminary design is a fundamental course of landscape architecture specialty. It has direct effect on students’ basic design abilities. Combining with the influence of current development in landscape architecture, the method of design research was introduced in the teaching process to build a research teaching system for the preliminary design course of landscape architecture, which was constituted of a mainline including a theoretical basis, the practice and investigation, the analysis and research, and the preliminary designing. The teaching system is beneficial for teachers’ teaching and students’ learning, and it can promote the teaching quality.