The invention discloses a railway engineering machine hybrid power source switching system which comprises a hybrid power source and a converter connected with the hybrid power source. The hybrid power source comprises an overhead line system power supply module and an internal combustion power supply module, and electric energy from the overhead line system power supply module or the internal combustion power supply module is converted through the converter and treated to form electric energy needed by a traction motor; when the system is electrically connected and communicated with an overhead line system and the overhead line system is continuously powered, the traction motor is powered by the overhead line system power supply module. When the system is electrically disconnected with the overhead line system or the overhead line system is not continuously powered, the traction motor is powered by the internal combustion power supply module. When the two power supply modules need tobe switched, the traction motor is powered by both the overhead line system power supply module and the internal combustion power supply module at the same time in the switching process, and the replaced power supply module exit from power supply after switching is ended. The technical purpose that it is ensured that the operation mechanism can continue to work and no impact exists when the two power sources are switched can be achieved.