To study the structural behaviors of the paraffin-based phase-change material (PPCM)-mixed clay core wall, including the stress, deformation, seepage and hydraulic fracturing, this work constructed a seepage-stress coupled analysis model for a core-wall dam filled with PPCM-mixed clay (PPCM-Clay) based on finite difference method. Then, the distributions of stress, deformation, seepage fields and hydraulic fracturing behaviors are analyzed for the core wall filled with PPCM-Clay and conventional clay under two conditions (right after construction completed and after impoundment), following with analyzing the feasibility of mixed filling with PPCM-Clay and conventional clay. Results under both conditions show that: the distributions of stress and deformation for PPCM-Clay core wall are basically consistent with conventional clay core wall, with a slightly higher maximum vertical displacement than conventional clay core wall; the distributions of permeability coefficient for the PPCM-Clay core wall is similar to conventional clay core wall, but with a higher level; the minimum safety coefficients meet the requirement of specifications, but most of which are lower than conventional clay core wall; the hydraulic fracturing will not occur in both PPCM-Clay core wall and conventional clay core wall. It’s feasible to fill core wall with PPCM-Clay below 0 ℃ and fill core wall with conventional clay above 0 ℃, which can reduce the total PPCM content and address the issue that the core wall filled with PPCM-Clay would perform a higher maximum vertical displacement.