Abstract: Shallow geothermal energy, as a new environmentally friendly energy that can be regenerated, has broad prospects in the development and utilization. The reductionism method which has been used in studying linear problems, can be converted into the nonlinear processing method which is more in line with the geological conditions of nature by using the fractal theory because of the complicated regional geological conditions. This article discusses the fractal dimension of suitability zoning structure of shallow geothermal energy occurrence conditions and the relationship between the fractal dimension and size. Besides, the impact of the geometric properties of the planar landform on the fractal dimension values is also discussed. This research shows that shallow geothermal energy suitability zoning structure have obvious fractal characters, and its fractal dimension reflects the tortuous degree of suitability zoning outline. And the fractal number and the irregular degree of contour line established a positive relation. This article provides a new method to deal with the nonlinear problem for shallow geothermal energy investigation and evaluation, and has a strong theoretical and practical significance in application of fractal theory and shallow geothermal energy development.