The invention relates to the technical field of circuit board production, and discloses a manufacturing method of a PCB, comprising the following steps: S1, providing a first substrate having a firstthrough groove, a second substrate, a third substrate having a second through groove and a fourth substrate, and forming a circuit pattern on the surface of the fourth substrate; S2, sequentially laminating the first substrate, the second substrate, the third substrate and the fourth substrate, and forming a multilayer board by compression; S3, subjecting the multilayer board to copper immersion and electroplating to metallize the groove wall and the groove bottom of a first groove; S4, milling the groove bottom of the first groove at the top of the second through groove to form a second groove; and S5, forming a third through groove in the groove bottom of the second groove. The manufacturing method of the PCB according to the present invention realizes the mounting of the special-shapedcomponent and a plurality of components of different sizes, reduces the occupied space of the PCB, and forms a circuit pattern at the groove bottom of the stepped groove, which is beneficial to further miniaturization of the PCB.