Abstract: This paper studied the storage and diurnal change of various organic carbon pools in two rotifer (Brachinus plicatilis) culturing ponds with different models in Panjin Photosynthesis Fisheries Limited Company, Dawa County, Liaoning Province from May to June 2001. The results indicated that the mean storage of particulate organic carbon (POC) and dissolved organic carbon (DOC) in static water pond was 5.69±2.90 mg·L^-1 and 24.56 ± 2.12 mg·L^-1, and that in current water pond was 9.61±3.17 mg·L^-1 and 24.13 ± 2.91 mg·L^-1, respectively. The ratio of total organic carbon (TOC), DOC and POC in current and static water ponds was 1∶0.75∶0.25 and 1∶0.82∶0.18, respectively. The pond with a high POC concentration was also with a high DOC content. The diurnal change of POC and DOC in current water pond was bigger than that in static water pond, i.e., the POC concentration in current water pond increased in daytime (from 5:00 to 17:00), while that in static water pond was more stable. The POC concentration in the two ponds was decreased from 15:00 to 23:00 but increased from 23:00 to next 5:00, and its peak time was 17:00 for current water pond and 5:00 for static water pond. The DOC/POC ratio in current water pond was increased gradually in daytime (from 5:00 to 17:00), while that in static water pond was decreased. The DOC/POC ratio in the two ponds was increased at night, and tended to dicline from 23:00 to next 5:00.