Fabrication method of electronic package

An electronic package is provided, including: a circuit structure having opposite first and second surfaces, wherein first and second circuit layers are formed on the first and second surfaces of the circuit structure, respectively, the first circuit layer having a minimum trace width less than that of the second circuit layer; a separation layer formed on the first surface of the circuit structure; a metal layer formed on the separation layer and electrically connected to the first circuit layer; an electronic element disposed on the first surface of the circuit structure and electrically connected to the metal layer; and an encapsulant formed on the circuit structure to encapsulate the electronic element. By disposing the electronic element having high I/O function on the circuit structure, the invention eliminates the need of a packaging substrate having a core layer and thus reduces the thickness of the electronic package.