Siderite (FeCO3) is a widely distributed authigenic mineral found in marine and terrestrial sediments, playing a crucial role in regulating elemental cycles during early diagenesis and preserving key paleoenvironmental information. Despite its importance, the transformation pathways of siderite under complex sedimentary environments remain poorly understood. This study investigates sulfide-induced siderite transformations in the presence of phosphate, silicate, and humic acid, simulating the geochemical conditions of coastal sediments. In the dataset, the phosphate dynamics in the reaction with siderite and sulfide, and the original data of XRD patterns of siderite after various treatments were reported.