Variations of the irradiated defects, resistivity, carrier mobility ratio and ca rrier concentration in high-dose neutron-irradiated n-type Czochralski silico n have been investigated by means of Fourier transform infrared spectrometer, po sitron annihilation spectroscopy and Hall effect. After irradiated with fast neu tron, the sample transformed from n to p-type. Two types of acceptor centers th at contribute to the V22O22, V22O, VO22, V-O-V and V 44-type defects will appear after annealing at temperature of 450 a nd 600 ℃, respectively. After annealing at temperatures above 650℃, with the elimin ation of acceptors, the carrier mobility ratio and the carrier-type began to re cover and a type of donor related to the irradiated defects will appear. The eff ective annealing temperature is 750℃ at which the donor is formed, and anneal ing above 900℃ for 1h will eliminate the donor.