This work investigated the multiscale structure and gelatinization properties of different oil-modified crosslinked starches and their relationship with the texture and microstructure of surimi/starch composite gels. The results showed clusters were formed by the agglomeration of starch, with oil on the surface of granules. Oil modification did not damage the long-range crystalline structure but impaired the short-range ordered structure. A high oil modification degree was shown to weaken starch structure, in contrast to an adverse effect for a high crosslinking level. Furthermore, compared with crosslinked starches, Oil-CTS had lower pasting temperature and gelatinization enthalpy, a higher viscosity, and better gel-reinforcing effect. Correlation analysis revealed the texture of surimi/starch composite gels was negatively correlated with the helical structure and pasting temperature of starch, and positively correlated with final and setback viscosity of starch and the swollen size of starch granules in surimi gel.