In this study, after aging PS and PVC microplastics (MPs) with a UVC lamp (254 nm), the adsorption characteristics of heavy metals (As(III), Cu, Pb) were evaluated. MPs in pellet form were prepared in the form of fragments of 125 μm or less and aging in a UVC lamp for 0 h (virgin), 144 h, 360 h, and 600 h. The surface characteristics of the photoaging PVC MPs were analyzed by Fourier-transform infrared spectroscopy (FT-IR) (carbonyl index; CI), X-ray photoelectron spectroscopy (XPS) (O/C ratio), and contact angle analyzer. The CI was 1.63 in the virgin and increased to 2.19 after aging for 600 h, the O/C ratio increased from 0.14 to 0.24, and the contact angle decreased from 72.4° to 32.3°. This demonstrates an increase in oxygen-containing functional groups and a decrease in the hydrophobicity of PVC MPs with photoaging. Three heavy metals (As(III), Cu, Pb) were adsorbed to PS and PVC at 10, 20, 40, 80, and 160 mg/L for 48 hours, respectively. Changes in heavy metal adsorption according to aging were observed using the maximum adsorption amount Qm (mg/g) of the Langmuir isothermal adsorption model. For As(III) of PS, Qm was 2.69 mg/g in virgin, and adsorption was not performed after aging. The Cu of PVC was 2.49 mg/g in virgin and decreased to 0.61 mg/g in MPs aged 144 h. Pb was 1.271 mg/g and 1.605 mg/g for PS and PVC, respectively, confirming that the amount of adsorption increased with aging.