Abstract: The common comprehensive water quality models have high requirements for hydrological data and water quality data,and a large amount of measured water-quality data is needed to set initial conditions and boundary conditions during simulation. In addition,their index system is inconsistent with the water quality indicator required by China’s actual management. Practical application of these models is difficult. In order to solve the problem of inconsistency between the commonly used comprehensive water-quality model index system and water quality index required by China’s actual management,and to improve its practicability and usability,focusing on the growth and metabolism of chlorophyll-a and the balance of dissolved oxygen,and comprehensively considering the interaction of five water quality components including total phosphorus,ammonia nitrogen,permanganate index and so on,a 5X comprehensive water-quality model which is suitable for water environment management requirement in China is built. This model is systematically reconstructed and generalized on the basis of QUAL-II model to reduce the data demand for initial conditions. At the same time,the comprehensive water-quality model is coupled with a two-dimensional hydrodynamic model under the DEM grid. The coupled model conforms to the geographic information system standard and has strong portability. In this paper,the finite volume method is used to discretize the model equations,and the SIMPLEC algorithm is used to solve the flow field. Finally,the tridiagonal matrix algorithm（TDMA）and the alternate direction implicit method（ADI）are used to solve the discrete equations to get numerical solution results. Taking Bali Lake in Jiujiang City as the research object,this model is calibrated and validated. The PBIAS（percentage deviation）method is used to judge the performance of hydrodynamic and water-quality simulation. The results show that the hydrodynamic simulation PBIAS value of this model is 0.95%,which has excellent simulation effect. The simulation performance of several water-quality components such as dissolved oxygen,permanganate index and total phosphorous is excellent. The simulation effect of ammonia nitrogen is good,and the simulation effect of other water-quality indicators is satisfactory. In general,the model meets the actual requirements of China’s water environment management. Its mechanism is clear and it has strong usability and the value of further development. It is applied to the comprehensive simulator of the urban water cycle and water environment with the characteristics of“mountain-city-stream-lake-river”in Jiujiang City and good results have been achieved. It has a guiding significance for the realization of ecological civilization construction and the Yangtze River conservation strategy.