A single-wave-beam depth finder water depth gross error detection and correction method comprises the steps of inputting original water depth acquisition point sequence data, utilizing a water depth value to perform threshold value judgment and dividing a water depth acquisition point sequence into multiple terrain chains; judging weights of the terrain chains, marking the weights as P=0 or 2, restoring water depth acquisition points in the terrain chains with the terrain chain weights P=0, and marking the terrain chain weights as P=1 after restoration. For the original water depth value gross error handling problem, a terrain chain concept is creatively provided, a new single-wave-beam depth finder water depth observed value gross error detection and correction scheme is designed, and a single-wave-beam depth finding data processing result in the Yangtze river basin shows that the method has obvious detection and correction effects on various gross errors.