The invention provides a navigation radar co-frequency interference inhibition method based on spatial correlation. The method comprises the steps of: loading spatial sea area clutter continuous images, and synchronously recording an image sampling point number, a bus number, a direction number and a display mode; utilizing correlation among radar image signals in a spatial domain, carrying out correlation coefficient calculation on adjacent storage lines; carrying out classified statistics on correlation coefficient histograms of signal lines and noise lines, drawing corresponding probability density curves, utilizing a fixed threshold method to determine detection thresholds; and judging the noise lines and the signal lines through the detection thresholds; and utilizing a close line substitution method to restore the noise lines detected out. Aimed at the distribution characteristic that co-frequency interference on the radar images is represented as rayed noise in the radial direction, the sea clutter spatial correlation is utilized for noise detection, noise pre-processing is carried out on original radar images, the co-frequency interference is filtered out, and the sea wave parameter inversion precision is improved.