The present invention discloses a method for adjusting a tunable compensation filter within a communication device. The method includes the following steps: generating at least a detecting signal according to at least a pole of the tunable compensation filter; generating a transmitted signal according to the detecting signal; receiving the transmitted signal via a loop switch; generating a filtered signal by filtering the transmitted signal; generating a received signal by compensating the filtered signal; generating at least an indicating signal by comparing the detecting signal with the received signal; and determining whether to adjust at least a coefficient of the tunable compensation filter or not according to the indicating signal.