The surface plasmon resonance (SPR) induced photothermal and photoelectrocatalysis effects are crucial for catalytic reactions in many areas. However, it is still difficult to distinguish these two effects quantitatively. Here we used surface‐enhanced Raman scattering (SERS) to detect the photothermal and photoelectrocatalytic effects induced by SPR from Au core Pt shell Nanoparticles (Au@Pt NPs), and calculated the quantitative contribution of the ratio of the photothermal and photoelectrocatalysis effects towards the catalytic activity. The photothermal effect on the nanoparticle surface after illumination is detected by SERS. The photoelectrocatalytic effect generated from SPR is proved by SERS with a probe molecule of p‐aminothiophenol (PATP). The contribution ratio of the SPR‐induced photothermal and photoelectrocatalytic effects during catalytic reactions can be detected. The photothermal effect can be measured by surface‐enhanced Raman scattering (SERS), and the photoelectrocatalytic process can be proved by SERS using p‐aminothiophenol as the probe molecule.