The invention provides a method and a system for correcting pulse transit time (PTT) associated with arterial blood pressure or a blood pressure value (BP) calculated by the PTT, which are able to correct abnormal change of the PTT of a subject caused by cardiovascular diseases or various medical interventions or abnormal change of the BP calculated from the PTT. The invention real-timely detects pulse wave signals from the proximal end and distal end in each cardiac cycle, calculates the PTT and extracts one or more feature data and feature factors from the pulse wave signals； based on one or more feature factors, determines a cardiovascular state of the subject and a change in the state, and obtains one or more correction variables in each cardiac cycle； obtains a correction matrix based on the correction variable, and corrects the PTT associated with BP or the BP calculated by the PTT.
