The invention discloses a river plane two-dimension current model roughness calibration method comprising the following steps: 1, delimiting roughness zones according to river plane features, and initializing the roughness in each zone; selecting the present flow rate with to-be-calibrated roughness and the corresponding river reach outlet water level; using a river plane two-dimension current mathematics model to carry out water-power calculation; determining errors between a model calculated value and an actual measurement value of each monitoring point water level; determining whether the water level error is small enough or not; determining a water pass area according to the water depth, and using all monitoring point water level error interpolation to estimate the water level errors between all grid points in the water pass area; using a dichotomy to adjust the roughness of the grid points in the water pass area according to the water level errors of all grid points in the water pass area; further determining whether all to-be-calibrated flow rates have been calibrated or not; if yes, finishing roughness calibration, and storing the roughness calibration result. The method can reduce artificial interferences in an iteration trial process, thus solving the problems that an existing method is unclear in technical process, rigid in conditions, and hard to apply.