A multi-electric field synergistic strategy based on heterojunction construction and polarization engineering enhances carrier separation and migration, achieving excellent piezoelectric photocatalytic performance of g-C3N4 based materials. Here, through the in-situ growth of BiOCl nanosheets (BOCs) on g-C3N4 nanosheets (GCNs), a 2D/2D Z-scheme GCNs/BOCs heterojunction was successfully fabricated, and its outstanding piezo-photocatalytic property was demonstrated. Compared to individual BOCs and GCNs, the high degradation rate (97.64 %) of rhodamine B (RhB) can be achieved over the optimal composite (GCNs/BOCs-50) after 50 min irradiation. Inspiringly, the polarized GCNs/BOCs-50 composite degraded RhB almost completely within 30 min under the simultaneous light irradiation and ultrasound, which reduced the photocatalytic time by 40 %, and its k reached 0.1410 min−1 (12.59 and 2.48 times that of BOCs and GCNs). This work is of great significance for designing a novel heterojunction photocatalysts using polarized ferroelectric materials.