The invention discloses a treatment system for radioactive liquid waste of nuclear power plants and secondary waste thereof. The system includes a filter device, an evaporation device and a treatment sub-system for removing salt, wherein the upstream portions of the filter device, the evaporation device and the treatment sub-system for removing the salt are connected with a first liquid waste collecting groove separately, and meanwhile, the downstream portions of the filter device, the evaporation device and the treatment sub-system for removing the salt are connected with a second waste liquid collecting groove separately; the filter device is also connected with a concrete fixing device to process secondary waste produced by the filter device; the evaporation device is also connected with a concentrated-liquid drying device to process secondary waste produced by the evaporation device; the treatment sub-system for removing the salt is also connected with a waste-resin drying device to process secondary waste produced by the treatment sub-system for removing the salt. The treatment system for the radioactive liquid waste of nuclear power plants and the secondary waste thereof has the advantages that since various treatment processes are included in the system, the radioactive liquid waste with different properties can be disposed specifically, so that the system has universality; the system is capable of reducing waste production amount generated by the secondary waste, increasing the minimized level of radioactive waste of the nuclear power plants, and decreasing impacts on environment by operation of the nuclear power plants.