After the implementation of rural family contracted land system and rural tax-fee reform， the collective irrigation of peasant households in irrigated area to use big and medium-sized farmland water conservancy projects is dramatically reduced，on the contrary，the farmer households prefer to choose the irrigation method by self-organizing to construct small water conservancy facilities. In the process of the change from “big water conservancy” to “small water conservancy”，it is necessary to study the influence of peasant household irrigation method change on their time allocation. Based on Becker’s time and household production analysis framework， according to time allocation theory，by using sample data of 600 farmer households in Hubei Province， empirical research is conducted on the impact of irrigation method on farmer household time allocation，and the results show that the change of farmland water conservancy irrigation method has big effect on farmers’time allocation， that the probability of non-agricultural money-making by the farmer households to use collective irrigation is higher than that of the farmer households to use family irrigation，the former uses longer time and may obtain higher income than the later，however，the change of irrigation method has insignificant impact on leisure time of the farmer households.