In this project, ZnTe quantum dots (QDs) on multi-walled carbon nanotubes (MWCNTs) by applying a facile and solvothermal method and characterized the various analysis material such as X-ray diffraction, dynamic light scattering, scanning electron microscopy, ultraviolet–visible spectroscopy. The outcomes indicated that the ZnTe QDs supported on MWCNTs in the catalyst. The ZnTe QDs on the MWCNTs, which that transport of generated electrons and leading to separation of photo-generated carriers in the coupled catalyst system. The photo-degradation performance of ZnTe–MWCNTs nanocomposites was studied by the decomposition of penicillin G (PENG) as a target compound. The results illustrated that the prepared ZnTe–MWCNTs nanocomposites exhibited higher photo-activity for the degradation of PENG than the pure ZnTe and MWCNTs under ultraviolet light irradiation. The optimal factors of PENG degradation were time: 60 min, and pH: 7.0, for the photo-degradation reaction medium.