Objective The relationship between pulse transit time (PTT) and invasive systolic blood pressure is analyzed with the data in MIMIC Database. A signal acquisition system which can obtain real time ECG and pulse signal is developed with AVR microcontroller and PC to analyze the relationship between the noninvasive systolic pressure and PTT. Methods Signals of 5 persons in the MIMIC Database are handled with Matlab software. The correlation coefficient between PTT and invasive systolic pressure is obtained. Six recruited normotensive male subjects (aged 27 to 31years) are tested with the system. Data of ECG signals and PPG signals are sent to PC via blue tooth. Then a two-month repeatability test is conducted on 4 subjects to test if there is a big change in the same subject. Results PPT has good linear relation with both invasive and noninvasive systolic pressure. Better linear relation can be achieved when the trough of the pulse wave is used as the characteristic point. Conclusions AVR data acquisition system is compact, portable, and can be applied in home care.