To achieve efficient aggregation of gold nanoparticles, obtain high-sensitive surface-enhanced Raman scattering (SERS) substrates, and study the photothermal effect of laser on the gold nanoparticles, a set of optical manipulations combined with a micro Raman spectroscopy system was developed, which has the combined functions of micro imaging, SERS detection, and optical manipulation. The influence of the photothermal effect on the gold nanoparticles in a solution and the SERS signal enhancement effect of pyrene were studied. Theoretically, the electric field enhancement effects of aggregated and single gold nanoparticles are calculated using the finite difference time domain (FDTD) method. The results show that the gold nanoparticles in the solution formed aggregates on the surface of the quartz substrate due to the thermophoretic force and convection, and their aggregation speed was affected by the temperature of the environment. The intensity of the SERS signal of the analyte pyrene increased with an increase in the aggregation time, and its stable SERS signal intensity was 15 times stronger than that of the gold colloid solution. FDTD simulation shows that gold nanoparticle aggregates would yield a higher SERS enhancement factor than single gold nanoparticle, the enhancement factor of the aggregates was 1.30×10 ⁷. This study employed the photothermal effect to achieve optical manipulation of gold nanoparticles (large-scale and high-efficiency capture of gold nanoparticles). This method can significantly improve the SERS effect of gold nanoparticles and has potential in detection and analysis in fields such as chemistry and biology.