Surface-enhanced Raman scattering (SERS) is a spectroscopic technique capable of accurately analyzing the compositions of materials at low concentration (volume fraction). In the case of metallic nanostructures, SERS enhancement is dependent on the electromagnetic field enhancement caused by the localized surface plasmon resonance (LSPR). In recent years, various LSPR metallic nanostructures are widely employed in SERS research, such as nanoantennas, nanoholes, and nanogrooves. However, once manufactured, these structures are immutable, which cannot meet the flexibility required by Raman detection. This problem can be solved by optical tweezers. In this paper, we develop a method of trapping gold nanocubes by optical force and facilitating gold nanocubes aggregation by photothermal convection. On this basis, the Raman signal at a low concentration (10 ^-12 mol/L) is significantly enhanced and detected, with the enhancement effect being better than that of gold nanospheres. Compared with traditional SERS, the proposed method has the advantages of real-time operation, dynamic operation and in-situ operation, thus showing potential application values in many important fields such as biological cell detection, analysis of substance composition and structure, and molecular sensing.