A lead frame has a metal base, a silver-plated layer, and a silver oxide layer. The silver-plated layer is formed between the metal base and the silver oxide layer. The silver oxide layer has a polar outer surface and a thickness of equal to or more than 1.3 nanometers. The silver oxide layer is beneficial to increase the adhesive strength between the lead frame and the molding compound and avoid delamination of the molding compound from the lead frame, so the lead frame of the present invention can pass a more severe moisture sensitivity level when exposed to the environment.