Abstract: The crud behavior in PWRs involves complex physical processes that consist of several subjects including material science, chemistry, thermal hydraulics, neutronics, etc. It could induce CIPS（CRUD induced power shift） and CILC（CRUD induced localized corrosion）phenomena which will not only lead potential risks to plant operation, but also influence the radioactive dose of the moderator and metal surface. Internationally, the US developed code BOA is widely adopted to perform risk analysis of CIPS and CILC, and the PACTOLE or OSCAR code developed in FRANCE is utilized to perform source term analysis of the corrosion products. Since 2018, CGN took three years to develop its own crud behavior code CAMPSIS 1.0. The code contains the core models of corrosion release, water chemistry, nuclide activation and crud deposition which makes CAMPSIS capable to perform risk analysis of CIPS and CILC and source term analysis at the same time. CAMPSIS has been verified against experiment data, measurements in normal operational conditions and shutdown periods. Results showed that CAMPSIS 1.0 is capable to perform crud behavior analysis in engineering-level.