In order to explore the biogenic theory of Huanglong travertine, the authors studied succinic acid,the typical extracellular organic acid of psychrotrophic bacteria isolated from Huanglong. By simulating the low-temperature sedimentary environments of Huanglong water body, the authors investigated the effects of succinic acid on the calcification kinetics as well as the morphology and polymorphism of CaCO₃. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to characterize the morphology and polymorphs of CaCO₃ precipitation. The results were listed as followes: ① High concentration, low pH value and temperature inhibit the calcification to a certain extent. ② High concentration of succinic acid induces the formation of vaterite. ③ High temperature improves the aggregations of microcrystals. In conclusion, succinic acid, as the typical extracellular organic acid of Huanglong psychrotrophic bacteria, participates in the process of sedimentation to a certain extent and plays a role in regulating the morphology and polymorphism of CaCO₃.The results can provide a basis for biogenic theory of Huanglong travertine.