Solid solutions can provide a more controllable way to realize the continuous regulation of the physicochemical properties of materials; thus, they have aroused extensive attention of researchers. Herein, one-dimensional (1D) Cd 0.85 Zn 0.15 S solid solution nanorods (CZS NRs) are selected as the substrate photocatalyst. Then, a uniform molybdate solid solution (Cd 0.85 Zn 0.15 MoO 4 , CZMO) nanoshell is successfully constructed on the surface of 1D CZS NRs for photocatalytic H 2 evolution (PHE) using a convenient in situ photoinduced ionexchange method with (NH 4 ) 6 Mo 7 O 24 •4H 2 O as a precursor. Compared with the CZS, the coated CZMO solid solution shell is more stable and can effectively protect the sulfide photocatalyst from photocorrosion. Meanwhile, as the reaction active sites, the CZMO shell also shows excellent affinity for water, and thus significantly promotes the adsorption and reaction of H 2 O molecules on the photocatalyst surface. More importantly, it is found that the in situ-constructed CZMO shell can form an intimate type-II heterojunction with the CZS core to further realize the efficient spatial separation of photogenerated carriers. The as-prepared core−shell CZS@CZMO solid solution heterostructure exhibits an enhanced and stable visible-light-driven PHE performance (∼8.5 mmol g −1 h −1 ) within 15 h of photocatalytic water splitting. On this basis, a preliminary mechanism model has been proposed.