The invention discloses a manufacturing method of a CWDM special optical module. The method comprises the following steps that 1, a module is installed, specifically, an installation module is taken out, and a control switch is turned on to enable an electric telescopic rod to extend, so that a left clamping block and a right clamping block are moved away; 2, a lower shell is installed, specifically, a control switch is turned on, the installation module in the step 1 is conveyed right above a lower shell telescopic rod, at the same time, the lower shell telescopic rod extends, and the lower shell is jacked up to the bottom of the installation module; and 3, an upper shell is installed, specifically, an upper shell telescopic rod works, the upper shell is pushed to fall into an installation groove, and then the upper shell is clamped with a lower shell assembly part. The manufacturing method relates to the technical field of electronic components. According to the manufacturing method of the CWDM special optical module, the installation module adapted to a PC board and an electronic component assembly is arranged, and only the assembly needs to be clamped in the installation module, so that the automatic installation can be realized, the finishing efficiency is improved, a large amount of labor is also saved, and meanwhile, the mechanical dimension is accurate, and the product installation quality is effectively ensured.