Precipitation elasticity is an efficient index to quantify the sensitivity of streamflow to precipitation changes in watersheds. It provides us with a tool to understand the historical and predicted changes in streamflow, which is key to assess the impact of climate change on water resources. This chapter provides the details of three frequently used methods for estimating precipitation elasticity of streamflow and a case study on the temporal and spatial variability of precipitation elasticity and runoff coefficient in 164 watersheds in China. The precipitation elasticity is estimated by a non-parametric estimator in three periods of interest. The results bring evidence of an association between spatiotemporal patterns of streamflow changes and precipitation changes, which suggest that climatic change is a dominant factor of annual streamflow changes in the investigated watersheds. In most watersheds, the precipitation elasticity of streamflow is larger than 1, indicating that a 1 per cent change in annual precipitation would result in more than a 1 per cent change in annual streamflow. The precipitation elasticity in watersheds with a small runoff coefficient is generally larger than that in watersheds with a large runoff coefficient.