The invention relates to a testing method of signal frequency bands and out-of-band interference levels. The method comprises the steps that a computer terminal starts a carrier communication testingitem, and sends out a carrier communication command to a measured concentrator or a copying-reading device through a communication interface; data of a measured carrier list is received, and whether carrier communication is successful or not is judged; a testing system is notified through the communication interface, and an industrial personal computer starts a testing procedure control program ofthe item; after a spectrometer inside the testing system completes carrier testing and sends level parameters, the industrial personal computer sends out a test stopping command; the work state of the testing system is adjusted according to a carrier communication result, and testing data stored by the industrial personal computer is read from the communication interface and processed. Accordingto the testing method of the signal frequency bands and the out-of-band interference levels, testing is conducted according to a DL/T 698 given method, sampling signals pass circuits like isolation level conversion, aiming at sampling of a sending end and a receiving end, a spectrometer is re-sent to conduct measurement to obtain actual carrier levels, the testing stability is high, and the anti-interference capability is high.