The invention provides a radio frequency unit and a method for adjusting signal amplitude. The radio frequency unit comprises an auto gain control and analogue to digital conversion module and a control and maintenance module, which is characterized in that the invention also comprises an amplitude adjusting module connected to the control and maintenance module to used for adjusting the amplitude of the radio frequency unit signals from the auto gain control and analogue to digital conversion module through a predetermined method according to shift parameter m or amplitude adjustment coefficient A which are calculated by the control maintenance module. The parameter is either of a shift parameter m or an amplitude adjustment coefficient A.. By utilizing the invention, AGC inconsistency in various radio frequency units can be eliminated to some extent, thereby reducing the adverse impact caused by AGC inconsistency and greatly increasing ultimate capacity of coverage area of each radio frequency unit.