利用功率譜分析探測DNA序列編碼區的主要特征信號三周期性，需要計算1/3頻率點的傅里葉頻譜。針對該問題，提出了只計算1/3頻率點處的傅里葉頻譜快速預測DNA序列編碼區的方法。理論分析和實驗證明，該方法的計算速度比使用傅里葉變換或快速傅里葉變換的方法快，計算準確性保持不變，不需要一個訓練組或現有數據庫的信息。The major signal in protein coding regions of genomic sequence is three-base periodicity. We use Fourier transform as a spectral analysis tool for genes detection, all that is required is a spot Fourier coefficient at M/3, and the complete Fourier spectrum is not required. An algorithm for computing spot Fourier coefficients is presented. Thereby, a method is developed to recognize the protein coding region of genomic sequence quickly. An important feature of the method is that its computational speed is very fast. Furthermore, this method is independent of training sets or existing datebase information and thus can find general applications.