A light emitting diode (LED) and a forming method thereof are provided. The method for forming the LED includes: providing a semiconductor substrate (20) and a sapphire substrate (30) respectively, wherein a first bonding layer (21) is formed on the silicon substrate (20), and a sacrificial layer (32), an LED die (33) and a second bonding layer (35) are formed in turn on the sapphire substrate (30); bonding the first bonding layer (21) and the second bonding layer (35); removing the sacrificial layer (32) and lifting off the sapphire substrate (30). The method increases the effective lighting area of the LED, improves heat radiation, and enhances lighting efficiency.