A static multi-scale finite element model interactive modification method based on improved quantum genetic algorithm was proposed aiming at the disadvantages of traditional finite element model modification methods, which are low efficiency, high cost and easy to fall into local extremums. The quantum bit vector states were encoded by real numbers according to the quantum computing theory, and the rotation angle was adaptatively updated by improving the quantum revolving gate. The improved quantum genetic algorithm was designed by introducing the quantum global interference crossover, mutation, catastrophe and other genetic operations. A multi-scale finite element model was established with a steel-concrete composite girder bridge as the engineering background. The objective function was established, the correction region was partitioned, and the maximum mutual information coefficient was used to screen the parameters and obtain the weight of the objective function. The interactive modification of static multi-scale finite element model based on improved quantum genetic algorithm was realized by Python language. Results show that the improved quantum genetic algorithm has higher performance and accuracy than the traditional genetic algorithm and quantum genetic algorithm, and the automatic interactive modification method is more efficient. The modification of material elastic modulus, thickness, vehicle load and other parameters accorded with the actual engineering test. The deflection error was reduced to 1.4%-14.3%, the stress error of concrete floor was reduced to 2.6%-18.8%, and the stress error of steel beam was reduced to 0%-11.1% compared with the initial finite element calculation.