The invention discloses a cold water evaporator with shell connected in series, copper pipe shared and single partition plate. The evaporator comprises shells, a front end cover, a front separation plate, an partition plate, a rear end cover, a rear separation plate and a copper pipe, wherein the shells are a cylindrical cast iron shell; a plurality of sections of the shells are connected in an end-to-end mode in series and are sealed together; a refrigerant inlet is located at one third of a center line of a side wall of the shells, and a refrigerant outlet is located at the top of the shells; the refrigerant inlet and the refrigerant outlet are far away from each other in the axis direction of the shells; bolt holes are formed in the edge of a pipe shell and a bottom shell of the front end cover; the two ends of the partition plate are welded to the end parts of the two sections of the shells correspondingly; and a water cavity is formed between the rear end cover and the rear partition plate; and the copper pipe is arranged in the shells. According to the cold water evaporator with shell connected in series, copper pipe shared and single partition plate, refrigerant pipelines are arranged in each independent shell, so that space occupation is reduced; the water in the copper pipe can be fully utilized for heat exchange; and the heat exchange efficiency is improved.