The invention relates to a toothed groove type tube-sheet evaporative cooling heat exchanger and an air conditioning unit. The heat exchanger comprises a plurality of heat exchange pipes connected insequence, heat exchange connecting pipes used for communicating of the adjacent heat exchange pipes, and heat exchange assemblies connected to the outer circumferential sides of the heat exchange pipes, wherein the heat exchange assemblies are provided with heat exchange channels which are connected with the heat exchange pipes in a sleeve manner, a plurality of toothed grooves are uniformly formed in the side of connection between the heat exchange channels and the heat exchange pipes, and toothed parts for contacting the heat exchange pipes are formed between the adjacent toothed grooves. According to the heat exchanger, when the heat exchange pipes are expanded, the toothed grooves form receded structures, expansion force parts of the heat exchange pipes can be converted into expansiondeformation of the heat exchange pipe groove type parts, the contact area with the heat exchange pipes during expansion is reduced through the toothed groove type structures, so that the acting forcebetween an integral heat exchange plate and the heat change pipes during expansion is lowered, the assembly difficulty of the tube-sheet type heat exchanger is reduced, meanwhile, due to the fact thatthe toothed groove type structures are arranged on the heat exchange plate, the heat exchange tube structures protruding through the expansion force can be partially receded, the situation of expansion cracking can be avoided, and the quality of products is guaranteed.