A quad flat no-lead (QFN) package structure including a lead frame, a semiconductor die, and an encapsulating material. The lead frame includes a die pad and a plurality of contacts surrounding the die pad. The semiconductor die is disposed on the die pad and electrically connected to the plurality of contacts, wherein a shortest distance between the semiconductor die and a first side of the die pad is shorter than a shortest distance between the semiconductor die to a second side of the die pad, and the first side is opposite to the second side. The encapsulating material encapsulates the lead frame and the semiconductor die and partially exposing the plurality of contacts, wherein an aspect ratio of the QFN package is substantially equal to or greater than 3.