A method for successfully obtaining detector-grade CdZnTe:In (CZT:In) crystals by annealing is described in this article. Pure Te is used as annealing source, which can provide sufficient deep-level Te antisites. Characterizations reveal that the resistivity is greatly enhanced by more than five orders after this annealing, thus the crystals can be use for radiation detectors. This is due to introduce efficient Te antisites to pin the Fermi level to the middle of the band gap. The EPD of dislocation reduces because the star-like Cd inclusions are eliminated by annealing. Investigation of annealing time shows that 240 h annealed CZT:In crystal with 7.8% energy resolution and 2.01x10(-3) cm(2)/V mu tau value has the best detector performance.