The present invention relates to a structure of a composite lead frame generally having a die bonding layer and a solder layer and may further have an cohesive layer between the die bonding layer and the solder layer. The die bonding layer is made of flex substrate and the solder layer is made of traditional lead frame. Thus, the composite lead frame structure is suitable for the flip chip or wire bonding packaging process of LED and also suitable for semiconductor IC packaging process. It is good in electric and heat conductivity, and also with higher mechanical strength, resulting high pin counts and minimization of resulted IC.