Microbially induced calcite precipitation (MICP) provides a promising approach for the in situ stabilization of cationic heavy metals in soil; however, substantial challenges remain regarding arsenic (As) remediation and the long-term stability of treatment effectiveness. In this study, urease-producing bacteria isolated from As-contaminated calcareous soil, together with six natural attapulgite types, were applied for 150 days in both laboratory and field experiments. The results demonstrated that calcium and nitrogen sources significantly influenced As remediation efficiency, with a maximum removal efficiency of 61% achieved at 60 mM calcium chloride and 6% urea. Compared with single treatments, attapulgite addition enhanced the transformation of labile As species into more stable fractions, primarily due to its water-soluble calcium content and the presence of chlorite and palygorskite. Combined bacterial and attapulgite treatment significantly increased urease activity and calcium carbonate accumulation while decreasing soil pH, indicating sustained microbial activity and ongoing biomineralization. Calcium-and iron-rich domains within attapulgite supplied calcium for microbial mineralization and facilitated As fixation through coprecipitation and embedding into aluminosilicate clay matrices, forming a calcium carbonate-based microbial metal pump. Arsenic concentrations in remediated maize grains and associated dietary exposure risks remained within safe limits. Overall, integrating locally abundant attapulgite with MICP represents a promising and scalable strategy for remediating As-contaminated calcareous soils.