In order to improve the anti-strong-laser-daxnage ability of (HgCd)Te detectors, a new technique has been proposed based on Franz-Keldysh effect. And a simple automaticprotection scheme using this technique has also been given in this paper. ExperimentalresultS show that this new technique is more effective and can be used to improve (HgCd)Te detectors' anti-strong-laser-damage ability in a large range.