This paper aims to examine the status of the supply reliability of groundwater irrigation, and discusses how it is affected by climate change and tube well density in rural China. Based on a large-scale, 9-province village survey and secondary climate data, results showed that on average, supply reliability was 89 percent in the past 3 years. Econometric results presented a non-linear relationship, which revealed that the annual temperature significantly influenced the supply reliability of groundwater irrigation. When the temperature is higher than the turning point (6.10C), the relationship between temperature and supply reliability of groundwater irrigation changes from being positive to being negative. Except for Jilin Province, the annual temperature in eight provinces was higher than the turning point. In the future, after keeping other factors constant, if the temperature increases by 20C, supply reliability will be reduced by 20%. However, if precipitation increases by 50%, supply reliability can be increased by 10%, while reducing precipitation by 50% will result in the reduction of supply reliability by 10%. Increasing the density of tube wells is greatly beneficial to supply reliability. However, although increasing the density of tube wells may ensure that enough groundwater is available for irrigation, such a conclusion is one-sided, and sustainability concerns should be raised in assessing this method of creating supply reliability.