In engineering applications， the loads acting on engineering structures are mostly distributed loads， so distributed load identification technology has always attracted much attention. The dynamic calibration technology identifies the load by establishing the relationship between the load and the response， and the traditional dynamic calibration method obtains the calibration matrix according to the finite element simulation， and the recognition results are affected by the model error. Based on the Gauss-Legendre integral， the infinite-dimensional dynamic calibration is converted into the finite-dimensional dynamic calibration， the time-domain indexing matrix is obtained through inverse Fourier transform and convolutional integration， the time-domain identification of the distributed load applied to the structure is carried out， and the effectiveness and high accuracy of the proposed method are verified by simulation. The noise is added to the response to test the noise resistance of the method， and compared with the traditional simulation calibration method. And the influence of the total number of Gaussian points on the recognition accuracy is discussed.