Abstract: Influenced by the characteristics of the relationship between people and land in mountainous areas, small mountainous cities often face the dual pressures of incremental spatial expansion and protection of the landscape environmental quality. The traditional approach is based on height index control for capacity measurement to create more incremental space, which lacks the “bottom line” control to protect the urban landscape ecological pattern and form the “mountain-city” visual interactions. Focusing on the construction of the “mountain-city viewing system”, this research analyzes how the two visual mutual feedback modes, “mountain viewing city” and “city viewing mountain”, make technical requests of the city’s overall height pattern protection and height space order, to form specific height indicators and morphological strategies. Taking the central urban area of Yongjia County in the mountainous area of southern Zhejiang Province as an example, this research systematically summarizes the building height and form control technology methods specifically for small mountainous cities in ecological civilization construction, by establishing a control technology path from the overall height control model to the hierarchical control mechanism, and to the meso-micro height form correction.