ZnIn₂S₄ has emerged in water splitting and degradation of dyes due to its good stability and light absorption properties. However, there are still few reports of CO₂ photoreduction. Herein, we successfully synthesized ZnIn₂S₄ and obtained a series of ZnIn₂S₄-CdIn₂S₄ heterostructured microspheres through the ion exchange method, and first used them in photocatalytic CO₂ reduction in noble-metal-free systems. The activity results showed that these ZnIn₂S₄-CdIn₂S₄ photocatalysts exhibit excellent catalytic activity under visible light, and the best CO yield is as high as 33.57 μmol·h^-1 with a selectivity of 91%. Furthermore, the stability and reusability of ZnIn₂S₄-CdIn₂S₄ was firmly confirmed by diverse characterizations, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX) and N₂ adsorption measurements.