A distributed spectrum analyzer and a method of spectrum analysis applying same. The spectrum analyzer adopts a separate design. A radio frequency receiver receives a signal, performs frequency conversion processing and AD conversion on the received signal, and sends the converted digital signal to a host. In such a structure, by a digital optical module, the radio frequency receiver is connected to a corresponding digital optical module on the host through an optical fiber, so as to implement a bidirectional data transmission. The host performs general control of the system as well as signal processing and spectrum analysis. Therefore, a multi-interface design is applied to the host of the spectrum analyzer, so as to support simultaneous access and control for a plurality of radio frequency receivers, thereby conveniently implementing multi-port measurement extension.