In this work, we report a facile process for the synthesis of coreshell hybrid nanocomposites for nearinfrared (NIR) photocatalysis by a two-step wet-chemical method. The core is composed of NaYF4:Yb/Er upconversion nanoparticles prepared by hydrothermal process, and the shell comprises of CdS semiconductor, whose bandgap matches the wavelength of the light emitted by the upconversion nanoparticles. A colored dye (methyl orange) and a colorless fungicide (carbendazim) were utilized as model pollutants to investigate the NIR driven photocatalytic performance of NaYF4:Yb/Er@CdS hybrid coreshell nanocomposites. To understand the nature of NIR-responsive photocatalysis of NaYF4:Yb/Er@CdS nanocomposites, we investigated the energy transfer between NaYF4:Yb/Er and CdS, which shows that the energy transfer route between NaYF4:Yb/Er and CdS is an important factor that governs the photocatalytic performance of the materials. Furthermore, the degradation of organic pollutants under NIR light is predominantly by the oxidation of reactive oxygen species formed during the photocatalytic reaction, rather than by the thermal energy generated by NIR light. A mechanism for NIR driven photocatalysis has been proposed and discussed.