A signal adjustment method, a signal adjustment circuit, an image processing circuit and a display device are disclosed. The signal adjustment method is used for adjusting a display signal including an original clock signal and an original data signal, and the method includes: delaying the original clock signal by a first delay amount to obtain a reference clock signal; delaying the original data signal by a second delay amount to obtain a reference data signal; sampling the reference data signal with the reference clock signal to obtain a sampled data; comparing the sampled data with a reference data to obtain a comparison result; and adjusting a reference timing relationship according to the comparison result, and the reference timing relationship is a timing relationship between the reference clock signal and the reference data signal.