A fabrication method of a chip scale package is provided, which includes forming a protection layer on the active surface of a chip and fixing the inactive surface of the chip to a transparent carrier; performing a molding process; removing the protection layer from the chip and performing a redistribution layer (RDL) process, thereby solving the conventional problems caused by directly attaching the chip on an adhesive film, such as film-softening caused by heat, encapsulant overflow, warpage, chip deviation and contamination that lead to poor electrical connection between the wiring layer formed in the RDL process and the chip electrode pads and even waste product as a result. Further, the transparent carrier employed in the invention can be separated by laser and repetitively used in the process to help reduce the fabrication cost.