A new algorithm of k-clock delay correction for swept source optical coherence tomography is proposed. The algorithm is based on cross correlation operation and can effectively correct the delay of the swept source k-clock signal. Due to the instability of the swept source and the external environment, as well as lack of precision of the synchronous trigger hardware, the k-clock signal of the swept source may have an uncertain delay with the interference signal when resampling the interference signal, resulting in decreased system resolution. A standard k-clock signal is acquired by experiments, and then the delay of the k-clock signal is calculated using the cross correlation operation. According to the calculated delay, the k-clock signal is shifted left or right to correct the difference with the standard k-clock, and then the corrected k-clock signal is used to resample the interference signal at evenly wavenumber domain interval. The experimental results show that the system performance is improved. The average running time of the algorithm is 0.18 s, and the resolution of the system is improved by 18.2%.