Aggregation of metal nanoparticles plays an important role in surface enhanced Raman scattering (SERS). Here, a strategy of dynamically aggregating/releasing gold nanoparticles is demonstrated using a gold-nanofilm coated nanofiber, with the assistance of enhanced optical force and plasmonic photothermal effect. Strong SERS signals of rhodamine 6G are achieved at the hotspots formed in the inter-particle and film-particle nanogaps. The proposed SERS substrate was demonstrated to have a sensitivity of 10 12M, reliable reproducibility, and good stability.