This paper adopts a multi-period double difference method to match city data and railway data of 10 prefecture-level cities in Zhejiang Province, except Zhoushan City, from 2006 to 2019 to explore the impact of the opening of high-speed railway (HSR) on the income gap between urban and rural residents. The study finds that the opening of HSR and the increase in the frequency of railway trains have substantially increased the real accessibility of cities in Zhejiang Province； The opening of HSR as a whole widens the income gap between urban and rural residents in prefecture -level cities in Zhejiang Province, with changes in urban accessibility caused by changes in the frequency of railway trains playing a mediating role, and there is heterogeneity in the number of districts and counties served by HSR in this effect； There is an early effect of the impact of HSR, which narrows the income gap between urban and rural residents in the region from the time when HSR construction begins.