Water sources of many mountainous rural areas are usually mountain streams in which the turbidity increases significantly during the rainy season due to the influx of sediment and debris carried by the rainwater. This paper takes the A village water purification plant project as an example, analyzes the existing problems of the current water purification plant, and proposes the adoption of ultrafiltration technology to effectively address these issues. At the same time, a technical and economic comparison between conventional treatment process and ultrafiltration technology is made, highlighting the advantages of ultrafiltration technology in both technical and economic aspects. The practical application of ultrafiltration technology in the design of water purification plant in mountainous rural areas is discussed, and the practical operational performance is revealed that ultrafiltration process has superior effluent quality and remains highly stable under conditions of unattended operation and maintenance.