Two-photon microscopy (TPM) has provided critical in situ and in vivo information in biomedical studies due to its high resolution, intrinsic optical sectioning, and deep penetration. However, its relatively small field of view (FOV), which is usually determined by objectives, restricts its wide application. In this paper, we propose a segment-scanning sensorless adaptive optics method to extend the FOV and achieve high-resolution and large-FOV two-photon imaging. We demonstrated the proposed method by imaging fluorescent beads, cerebral nerve cells of mouse brain slices, and cerebral vasculature and microglia of live mice. The method extended the FOV of a commercial objective from 1.8 to 3.46 mm while maintaining a lateral resolution of 840 nm and high signal-to-noise ratio. Our technology is compatible with a standard TPM and can be used for large-scale biological exploration.