Abstract: The forest condition in southwestern Guizhou was good in the middle and late Ming Dynasty, but great changes took place in the Qing Dynasty. From the early to the middle of the Qing Dynasty, the forest declined gradually, and the forest declined sharply in the late Qing Dynasty. Although the forest decay in southwestern Guizhou in Qing Dynasty was related to the fragile karst geographic environment, in essence, human-made social factors were the fundamental driving force for forest decay and even rocky desertification. The contradiction between man and land caused by the sharp increase of population is the root of forest attenuation, and the forest consumption formed on this basis directly contributes to forest attenuation.