The invention relates to a production method for a granular compound mixed nitrogen fertilizer. The production method comprises the following steps that 1, ammonium nitrate fertilizer granules or ammonium nitrate phosphate fertilizer granules are fluidified and preheated to 40 DEG C-60 DEG C; 2, liquid urea or urea melt liquid is sprayed to the preheated fertilizer granules and wrapped with the fluidified fertilizer granules to be granulated, and then the granular compound mixed nitrogen fertilizer is obtained. According to the granular compound mixed nitrogen fertilizer prepared through the production method, the three nitrogen sources of nitrate nitrogen, ammonium nitrogen and amidonitrogen are integrated into a whole, therefore, package, storage and transportation are convenient, the cost is lowered, and safe application of farmers is facilitated; meanwhile, the phenomenon that moisture absorption is prone to occur after common urea granules and ammonium nitrate granules are mixed is avoided.