Abstract: Objective To evaluate the key quality control and protective performance test of Halcyon medical linear accelerator. Methods WS 674-2020Specification for Testing of Quality Control in Medical Linear Accelerator（ According to the hereinafter WS 674-2020） ， referred to and the manufacturer´s manual the performance of the first Halcyon medical linear accelerator in Results ， ， Hunan Province was tested. The results showed that all ten indicators of the accelerator including dose deviation ， ， （ ， ， ， - repeatability linearity daily stability and symmetry the results were 0.10% 0.03% 0.04% 0.50% and 100.50% 100.80% ）， - - respectively met the requirements of WS 674 2020. The results of manufacturer quality control indicators such as dose rate ， ， stability in beam gantry rotation isocenter and mechanical position accuracy megavolt image parameters and cone beam computer tomography image parameters met the requirements of the manufacturer´s regulations. Due to the special structure and ， - ： function of the accelerator it is difficult to detect the parameter required by WS 674 2020 as below the radiation leakage - ， ， ， ， outside the M zone the uniformity the indicators related to the light field the offset of the radiation beam axis the zero scale Conclusion - position of the rotating motion scale and others. It is difficult to carry out complete testing according to WS 6742020 for Halcyon medical linear accelerator and it is urgent for the state to issue relevant testing standards to standardize and strengthen the quality control testing of various accelerators.