The organic carbon budget in shrimp polyculture ecosystems was studied with five experimental enclosures.The results showed that: (1)the total organic carbon income of the ecosystems varied from 4 847.46 to 6 154.67 g, averaged (5 646.94±551.09) g, the average ratio among its components, i.e.,(phytoplankton production):(periphyte production):(feed tasted) was 0.73:0.11:0.16; (2) the total output of organic carbon varied from 3 310.28 to 3 974.79 g, averaged (3 644.21±1 281.44) g, the average ratio among its components, i.e.,(plankton community respiration):(periphyton respiration):(benthic community):(culture animal production):(culture animal respiration) was 0.53:0.19:0.15:0.04:0.09; (3) the organic carbon accumulation varied from 1 383.45 to 2 707.31g, averaged (2 002.73±1 546.76) g, which was 26%-44% of the total organic carbon income; the sequence of organic carbon accumulation in the ecosystems of different polyculture types was Y5 (Penaeus chinensis-Argopecten irradians) > Y7 (P.chinettsis-Taiwan red tilapia) > Y4 (P.chinensis) > T5 (P.chinettsis-Taiwan red tilapia-Sinonovacula constricts) > Y6 (P.chinettsis-S.constricts);(4) the average conversion rate of organic carbon income to P.chinettsis was (1.77±0.62)%(Y6 > T5 > Y4 > Y5 > Y7),and that to total culture animals was (2.18±0.79)% > (T5 > Y6 > Y5 > Y4 > Y7).