Abstract: This paper makes an analysis on the weather condition and physical climate effects, which cause the formation of icing in Hunan mountainous forests. After making a study on the differences of leaf-canopies, leaf and needle shapes, quantities of leaf and needle, branch shapes, forest structures and heights of altitude of various forests, the author put forwards some views of preventing from the icing to forests.1. Chinese fir plantations should be made mainly plantations of smaller acreage and to build up seperate forest belts with broad-leaf tree species in between.2. To carry out final felling at proper time and adopt appropriate cutting method.3. Masson pine should be planted in the altitude range of 300—500m, Chinese fir 700—1000m, bamboo 900—1300m or below 400m.4. To speed up the re-built of existing coppice forests.