The invention relates to a phase-coherent accumulation method based on frequency domain shear. When a target echo envelope walks over a range unit within a phase-coherent processing interval, the envelope walking track of a range-slowing-down time dimension signal space is regarded as an image and rotates and translates by a certain angle by a frequency domain shear processing method, each rotary transferring process is subjected to slowing-down time dimension fast Fourier transform to obtain phase-coherent accumulation peak values, so that each rotating angle corresponds to one accumulation peak value, the gradient and the start distance of a corresponding target track are obtained by the aid of the maximum peak value, and the movement track of a target is obtained. Range walking correction and target energy accumulation are effectively realized, and the phase-coherent accumulation method is applicable to radar dim target signal detection and range walking correction in radar imaging technology, high in precision, rapid in operation, easy in engineering realization and fine in robustness.