A blood pressure regulating system uses a native regulation rule to estimate at least one nerve activity in response to blood pressure changes, comprising at least one blood pressure sensing means which senses blood pressure and outputs a input blood pressure signal, a calculating means which receives the input blood pressure signal, calculates a transfer function by computing a Fourier transform of a normal blood pressure signal and a normal sympathetic nerve activity from normal cardiovascular system, calculates an impulse response by computing an inverse Fourier transform of the transfer function, calculates a sympathetic nerve stimulation signal using a convolution integral between the input blood pressure signal and the impulse response, and outputs the sympathetic nerve stimulation signal, and a stimulating means which receives the sympathetic nerve stimulation signal, and stimulates the sympathetic nerve innervating vascular beds based on the sympathetic nerve stimulation signal such that blood pressure is regulated.