Objective:　This　study　aimed　to　analyze　fetal　quiet　sleep　cycle　(QSC)　features　based　on　long-term　transabdominal　fetal　electrocardiogram.　Methods:　According　to　the　inclusion　criteria　(singleton,　36-40　weeks),　54　cases　were　enrolled　in　this　study.　The　Monica　AN24　recorder　was　used　to　record　continuous　15-h　fetal　heart　rate　data,　extracting　QSC　features　to　compare　different　nonstress　test　(NST)　types　and　analyzing　the　relationship　between　QSC　features　and　gestational　age　(GA).　Results:　The　QSC　proportion　of　valid　recording　length　of　NST　reaction　type　and　NST　suspicious　type　fetuses　was　12.9%　and　19.2%,　respectively.　Other　parameters　of　NST　suspicious　type　fetuses　were　higher　than　those　of　NST　reaction　type　fetuses.　At　the　same　time,　QSC　number　and　proportion　of　valid　recording　length　had　significant　differences　between　the　two　types.　The　parameters　of　NST　reaction　type　fetuses　had　an　increasing　trend　with　increasing　GA.　Conclusions:　The　features　of　NST　suspicious　type　fetuses　were　higher　than　those　of　NST　reaction　type　fetuses.　Analyzing　fetal　QSC　and　finding　a　suitable　threshold　value　would　help　lower　the　false　positive　rate　and　reduce　unnecessary　clinical　intervention.