The invention relates to a method for measuring key physiological parameters in noncontact manner, such as blood pressure and its change rate, electrocardiogram, blood oxygen saturation, respiratory frequency, and heart rate and its change rate. The key physiological parameters can be measured by analyzing plethysmographic signals and bioelectric signals collected by a sensor or a probe without contacting human body. The device adopted in the method has wider application scope than the conventional contact measurements, can be applied in particular environments such as mobile ambulance or battle field treatment, and can also be integrated in auxiliary facilities such as bathtub, bed and coach in everyday life. The device has the advantages of simple and easy operation, no affect to users' activities during measurements of physiological parameters, and no requirement of active intervention of users, and can provide safe, economical and practical, nondestructive real time continuous monitoring of physiological parameters for users.