Abstract: A high-efficiency extra-large cooling capacity series water-cooled chiller in an energy station, comprising at least two evaporators, a condenser, a chilled water main pipe and a cooling water main pipe, all the evaporators form an evaporator series set in a series connection form, both ends of the evaporator series set are connected to the chilled water main pipe, and each evaporator is provided with a refrigerant channel for connecting the condenser. According to the present invention, the evaporators are set in series combination. When the load is very low, one compressor operates at a high load or at full load, that is, the compressor continuously operates in a high efficiency zone, which avoids multiple compressors operating in an inefficient zone, and high total power.