An analog and digital auto-gain control method includes the steps of: providing a gain-mapping table; determining an analog gain level according to a power of a far-end transmitted signal; obtaining a gain-mapping value from the gain-mapping table according to the analog gain level; obtaining a digital gain value according to the gain-mapping value; and adjusting a gain of a digital signal according to the digital gain value. A receiver that performs the auto-gain control method is also disclosed.