The invention provides a refrigeration evaporator with each shell and inner evaporation copper pipes using a single spacing board in common. The refrigeration evaporator comprises shells, a front endcover, a front spacing board, spacing boards, a rear end cover, a rear spacing board and copper pipes, the shells are cylindrical cast iron shells, the multiple segments of shells are connected end toend in series and sealed, each segment of the shell is provided with a refrigerating agent inlet, a refrigerating agent outlet, an air exhausting mouth and an oil discharge mouth, the corresponding position, located inside the corresponding shell, of each refrigerating agent outlet is provided with a baffle in a welded manner, the edge of a bottom shell and a pipe shell of the front end cover isprovided with bolt holes, two ends of each spacing board are welded to the end portions of two segments of the shells correspondingly, the rear end cover is formed by welding a cylindrical shell of anouter ring and a spherical-surface type bottom cover, and the copper pipes are inside the shells. According to the refrigeration evaporator with each shell and inner evaporation copper pipes using the single spacing board in common, the space occupation can be reduced by connecting the shells in series together, and by means of the baffles inside the shells, the refrigerating agent is made to notbe discharged from the refrigerating agent outlets directly when the refrigeration evaporator is started.