Abstract: Forest can accumulate and store up water resources, conserve soil, and regulate climate, so it is the core of an ecosystem in mountainous and hilly area. The people in the lower reaches of Xijiang River in Qing Dynasty had a profound understanding on it; therefore they paid great attentions to the afforestation and forest protection. Concerning afforestation, they planted many kinds of trees such as ornamental forests, roadside trees, and protection forests. In the aspect of forest protection, the most salient thing was they set up inscriptions for protecting the forests. Through analyzing the contents of these inscriptions, we know that the people in the lower reaches of Xijiang River protected the forests with the combined help of religion, folk customs, ownership and the power of government. These measures not only reflected the wisdom of the local people, but also ensured the proection of the ecological environment of this area, which had contributed significantly to the ecological environment in the Pearl River Delta and even whole Guangdong Province.