The utility model relates to the technical field of continuously casting a metal, especially relates to a chamber crystallizer narrow-surface copper plate with a combined cooling water channel. A working surface of the narrow-surface copper plate (1) comprises a planar area and an inclined area (2), wherein the planar area is arranged in the middle part of the working surface, the inclined area is arranged on the edge corner parts at the two sides, the length L of the straight line on the cross section of the inclined area (2) is 5-150mm, round and rectangular cooling water channels which are vertically perforated, are distributed in the narrow-surface copper plate along the height direction, 1-6 rectangular water channels (5) with width of 4-8mm and 1-6 round cooling water channels (6) with diameter of 5-10mm are distributed in the inclined area (2). The chamber design of the chamber crystallizer narrow-surface copper plate facilitates the optimization of the narrow-surface shape of the blank and the combined cooling water channel in the chamber is used for controlling the crack defect on the edge corner part of the micro-alloy steel and facilitates the prolonging of the service life of the narrow-surface copper plate.