Radar-based vital sign detection method and device, radar and storage medium

The invention provides a radar-based vital sign detection method and device, a radar and a storage medium. The method comprises the following steps: when a user is in a bed, extracting vital signs of the user based on an echo signal obtained by detecting a bed body surface area by a radar; if the vital signs of the current vital sign monitoring period are smaller than a preset vital sign threshold value, distance units where a user is located and corresponding signal amplitudes in echo signals of continuous N calculation periods before the current vital sign monitoring period are obtained; if the distance unit where the user is located in the echo signals of N continuous calculation periods before the current vital sign monitoring period continuously increases and the corresponding signal amplitude continuously decreases, it is judged that the user has an off-bed action, otherwise, it is judged that the user does not have the off-bed action, and an alarm signal that the current frame of vital signs is weak is