This paper presents the design, implementation and test of a watch with the capability to measure multiple physiological signals, such as photoplethysmography (PPG), electrocardiography (ECG), and some physiological parameters extracted from PPG and ECG. Based on the PPG and ECG signals, the pulse rate and heart rate could be extracted respectively. Moreover, the pulse transmit time (PTT) could be extracted combining PPG and ECG, which was the key to calculate blood pressure (BP). The circumstance conditions (temperature, humidity and barometric pressure) were detected and displayed on the screen. A motion state was used to toggle the watch screen. Meanwhile all data measured could be sent to an android smart phone, using a Texas Instruments' (TI's) Bluetooth low energy chip CC2540. The PPG wave, ECG wave, heart rate, as well as the systolic blood pressure (SBP) and diastolic blood pressure (DBP) can be displayed on the android client in real time. Compared with the sport band and other smart watches, this multi-parameter health monitoring watch had the advantage of monitoring more parameters. We had made a test to compare this watch with standard equipment, Benavidez T5 and SUNTECH OSAR2, and the result showed that the relative error of heart rate, pulse rate, SBP and DBP against reference were 1.76 ±1.64bpm, 1.76 ±1.64bpm, 4.01 ± 2.75 mmHg, 4.64 ± 3.31 mmHg. These results demonstrated that this watch has a broad prospect in the field of mobile health care.