An obstructed area determination method and system for sleep apnea syndrome are disclosed. The obstructed area determination method includes: receiving a snoring signal of a subject; acquiring a spectrogram of the snoring signal using short-time Fourier Transform; obtaining a snoring signal feature from the harmonic wave of the spectrogram; and comparing the snoring signal feature to a snoring signal feature-collapse index correlation database to obtain the corresponding collapse index. The present invention enables the diagnosis of sleep apnea syndrome and determination the obstructed area for the sleep apnea syndrome with only the snoring signal of a subject during sleep.本發明提供一種睡眠呼吸中止阻塞位置之判斷方法及系統。睡眠呼吸中止阻塞位置之判斷方法包含:取得一受測者之鼾聲訊號;利用短時距傅立葉轉換取得該鼾聲訊號之聲譜圖;由該聲譜圖中之諧波取得一鼾聲訊號特徵;以及比對一鼾聲訊號特徵及氣道塌陷指數之關聯資料庫即可取得該鼾聲訊號特徵對應之氣道塌陷指數。本發明讓受測者只需測量睡眠時的鼾聲訊號,即可以簡單又準確的判斷睡眠呼吸中止症及判斷睡眠呼吸中止之阻塞位置。