The present invention relates to a blood pressure measuring system without arm strap, which utilizes an electrocardiogram detection module disposed on a subject's chest to detect the electrocardiographic signal of the subject； and, using the light sensing sub-module on a wearing type blood pressure measuring module worn on subject's limb to measure the photoplethysmography signal of the subject's limb, so as to compare the waveforms of both signals to find the pulse transmit time of the subject after heartbeat and further calculate the blood pressure information of the subject.本發明有關於一種無臂帶之血壓測量系統，其主要係透過設置於受測者胸部的一心電圖偵測模組來偵測受測者的心電描繪訊號，再透過配戴於受測者肢體上的一配戴式血壓測量模組上的光感應子模組來測量受測者肢體的光容積描繪訊號，以對兩訊號進行波形比對來找出受測者心搏後的脈波傳遞時間，再進而計算產生受測者的血壓資訊。
