The invention discloses a fetus-quiet-sleep-cycle extraction method based on a fetus heart rate curve. A signal input module, a deceleration identifying module, a quiet-sleep-cycle identifying module and a result output module are adopted in the fetus-quiet-sleep-cycle extraction method, wherein in the signal input module, signal pretreating and deceleration fragment extracting are carried out; in the fetus-quiet-sleep-cycle identifying module, effective signal selecting, parameter calculating and quiet-sleep-cycle identifying are carried out; output results include parameters such as the number of quiet-sleep-cycle times, the longest duration and average duration. According to the fetus-quiet-sleep-cycle extraction method, by means of original data obtained through a fetal heart monitor, the fetus-quiet-sleep cycle can be extracted, relative parameters can be output, and the reading efficiency of an electronic fetal heart monitoring graph can be effectively improved.