In this paper, we discuss the development of an easy-to-use non-intrusive endothelial function assessment instrument. The instrument records the digital pulse volume (DPV) from the fingers. We studied 42 subjects (28 men and 14 women, 22 to 64 years of age) and showed the good performance of self-developed system for monitoring endothelial function. The system is capable to apply both area under the curve of DPV and traditional amplitude methods for endothelial function assessment. Both methods are highly correlated as well as able to reflect the changes of blood flow volume in reactive hyperemia. At home, only a few minutes are needed for conducting a self endothelial function assessment. Therefore, early self-monitoring of cardiovascular dysfunction and arterial stiffness can be easily and effectively achieved.