In the swept source optical coherence tomography (SS-OCT) instruments, an unfixed delay between the spectral calibration signal k-clock and the OCT signal makes the result of spectral calibration incorrectly, which reduces the imaging resolution. An automatic delay correction algorithm is proposed to automatically correct the delay between k-clock signal and OCT signal accurately. The algorithm based on the proposed average peak method and average full width at half maximum (FWHM) method, through processing and analyzing the OCT signal, divides into coarse adjustment, fine adjustment and accurate adjustment to search for delay point automatically. According to the search result, the delay time is corrected. After delay correction, high resolution reconstructed image is realized through spectral calibration of OCT signal evenly distributes in the wave-number (k) space. Experimental results show that, the imaging resolution improves 60% by correcting the delay automatically, which proves the effectiveness of the proposed algorithm.