Abstract: In order to evaluate the construction effect of sponge city, it is necessary to sample and monitor the runoff process of the sponge facilities and areas with different scales. It is difficult for the existing sampling methods and equipments to automatically collect water samples at the initial stage of runoff generation. In this paper, a set of automatic sampling technology for urban rainfall runoff water quality monitoring was developed, which included a non electric driving natural rainfall automatic sampler, an automatic sampling terminal for water quality monitoring that could "zero capture" the underlying surface runoff, an intelligent automatic water quality sampler and other equipments. It solved the problem of collecting initial water samples of natural rainfall and runoff process automatically on any weather condition. It could also record the exact time of sampling process. The practical application showed that the technology had strong applicability, reliable performance and could support the related scientific researches and monitoring activities.