The invention provides a charge transfer efficiency test method of a post-neutron irradiation charge coupled device. According to the method, when the readout of CCD signal charges occur, an overscanning pixel output unit is additionally adopted; defects which are generated due to the induction of neutron irradiation are made to capture CCD signal charges; captured CCD signal charges are collected in the overscanning pixel output unit; signal charge loss generated by the induction of neutron irradiation can be displayed intuitively through image output; saturated illumination is adopted to eliminate the influence of dark signal peaks on signal charge packets in a process in which the signal charge packets are sequentially transferred between CCD transfer channels; and requirements for the consistency of the size of the signal charge packets in a charge transfer efficiency test (CTE) after different neutron fluence irradiation can be satisfied. With the method adopted, the problem that a CTE test is inaccurate or even if cannot be performed existing on the post-neutron irradiation charge coupled device can be solved.