A low noise amplifier (LNA) has been disclosed for the noise and linearity performance improvement. The LNA includes an amplifying transistor and an auxiliary transistor. The amplifying transistor includes a first terminal for receiving an input signal of the LNA, a second terminal for outputting an output signal of the LNA, and a third terminal. The auxiliary transistor has a first terminal, a second terminal coupled to the second terminal of the amplifying transistor, and a third terminal electrically connected to the first terminal of the amplifying transistor.