The present invention discloses a homologous dual-energy accelerator and a therapy device comprising the homologous accelerator. The homologous dual-energy accelerator comprises an electron emitting device and an accelerating device, wherein the electron emitting device is located at the input end of the accelerating device, and electrons generated by the electron emitting device are emitted from the output end of the accelerating device after being accelerated by the accelerating device; the homologous dual-energy accelerator further comprises at least one separation deflection device which is arranged on the output end side of the accelerating device and used for changing the motion trail of partial electrons among the electrons accelerated by the accelerating device. The homologous dual-energy accelerator has the advantages that the inventor discovers that the speeds and energy of all electrons are not completely same after the electrons are accelerated by the accelerating device; the inventor uses the separation deflection device arranged on the output end side of the accelerating device through the discovery, the motion trail of partial electrons having relatively low energy level among the particles accelerated by the accelerating device is forcibly changed, the electrons having different energy levels in a homologous electron beam are separated, and two energy levels of electron beams are thus obtained, wherein the high-energy electron beam continues an original path and is used for radiotherapy, and the other path of low-energy electron beam is used for tracking lesions and detecting the therapeutic effect.