To solve the problem that the traditional measurement method of axial length is segmented detection and the measurement error is large, a swept-source optical coherence tomography system with large detection range and realized one-time measurement of axial length was designed. In order to reconstruct the large depth interference signal, an algorithm combining adaptive peak point extraction and adaptive error correction was proposed. The CPU-GPU acceleration technology was used to realize the real-time measurement and solve the problem of great data and slow speed of wide imaging range. Optical eye model experiments shows that the measurement error of axial length is 0.01 mm, which is superior to the traditional segment measurement system. The single measurement time is 0.10 seconds, which meets the real-time measurement requirements.