Abstract. In this study a method for measuring the regional hydrological connectivity and water supply requirement of wetlands in Western Jilin Province (WJL) is defined and verified. The ecological water requirements of 216 wetlands, under various guarantee frequencies, were calculated and analyzed. In addition, twelve indicators were used to establish an evaluation index system, to characterize their ecological water requirements. The results showed that 12 hydrologically connected regions were delineated in WJL, and the 216 wetlands can be classified to six grades by AHP (Analytic Hierarchy Process) method. The annual minimum, suitable, and maximum ecological water requirements of these wetlands were found to be 7.72×10 8 m 3 , 13.76×10 8 m 3 , 26.15×10 8 m 3 respectively, with 50% guarantee frequency. The primary water supply to the lakes and marshes was found to be from regional sources that provided a scientific basis for the allocation of water resources from the interconnected river-lake system network (IRLSN) in WJL.