The present invention relates to a manufacturing method of an organic zinc catalyst having more uniform and finer particle size and showing a more improved activity in a polymerization process for manufacturing a polyalkylene carbonate resin, and a manufacturing method of the polyalkylene carbonate resin using the organic zinc catalyst obtained by the manufacturing method of the organic zinc catalyst, the manufacturing method of an organic zinc catalyst including: forming a zinc dicarboxylate-based catalyst by reacting a zinc precursor with C3-C20 dicarboxylic acid, wherein the reaction step is performed under a condition in which the number of moles of the dicarboxylic acid is more than that of the zinc precursor in a reaction system, throughout the entire reaction step.