A package of a semiconductor device with a flexible wiring substrate and a method thereof are provided. The package of the semiconductor device includes a semiconductor substrate with at least one pad on a surface thereof, a bump bonded to the pad, an adhesive layer on the bump, and a flexible wiring substrate having at least one contact section being electrically connected with the bump by the adhesive layer. The present invention makes the flexible wiring substrate directly conductively attached onto the semiconductor substrate. The package size is shrunk and the cost down can be obtained.