Control circuit and method of PCI-E (peripheral component interconnect express) device

A control circuit of a PCI-E (peripheral component interconnect express) device comprises a power detecting unit and a parameter adjusting unit. The power detecting unit is coupled to a wireless communication transmitter and used for detecting a spectral strength value of an output spectrum of the wireless communication transmitter. The parameter adjusting unit is coupled to the power detecting unit and used for generating at least one control signal according to the spectral strength value and adaptively adjusting parameters of the PCI-E device according to the at least one control signal.