From an ecological perspective, the nature of rainwater harvesting with the characteristics of artificial disturbance is a manual disturbance. So it is very important to confirm the degree of ecological disturbance that occurs due to rainwater harvesting. Drawing from ecological disturbance theory, we can utilize both the distance method and dynamic curve method to estimate the level of ecological disturbance and degree of rainwater harvesting with a historical reference point value of the environment as a frame of reference, and with the 20 indicators such as surface runoff and evaluation index. Our examples show that the distance method and dynamic curve method are feasible for evaluating the ecological disturbance degree of rainwater harvesting. There are also research-scale effects in the study of ecological disturbance of rainwater harvesting that embody the comparability of different spatial and temporal ecological disturbance degrees. The comparability of ecological disturbance degrees of rainwater harvesting in an area at different scales or in different areas at the same scales is not strong, but it also generates some useful reference values. The ecological disturbance measurement in the same study area and at the same research-scale at different historical periods can be compared.