This application provides a multi-band low noise amplifier, including: an input end, a first input matching network, a second input matching network, a first amplifier, and a second amplifier. The input end is coupled to an antenna and is configured to receive an inter-band carrier aggregation signal, where the inter-band carrier aggregation signal includes a first carrier signal located in a first band and a second carrier signal located in a second band, and the first band is different from and does not overlap the second band. The first input matching network is coupled between the input end and the first amplifier and is configured to perform impedance matching for the first carrier signal. The second input matching network is coupled between the input end and the second amplifier and is configured to perform impedance matching for the second carrier signal.