The invention relates to an X-band shore-based radar flow measurement method based on interrupted up-and-down frequency modulated waves. The method comprises the following steps: emitting interruptedup-and-down frequency modulated continuous waves by utilizing an X-band shore-based radar; performing up-down frequency modulation signal separation on a sea surface radar echo signal to obtain an up-frequency modulation echo signal and a down-frequency modulation echo signal; performing distance imaging on the up-modulation echo signal and the down-modulation echo signal by using a dechirping method; estimating the distance offset between the up-modulation one-dimensional range profile and the down-modulation one-dimensional range profile by using a transform domain straight line fitting mode; calculating the radial velocity of the ocean current according to the estimated distance offset; converting the up-modulation and down-modulation one-dimensional distance images from the slant distance coordinates to the ground rectangular coordinate system coordinates; and finally, splicing the radar images corresponding to different radar beam azimuth angles to obtain a two-dimensional sea surface radar image.