Based on the model coordinate transformation theory, the distributed load to be identified on BernoulliEuler beam structure in engineering structures can be decomposited in model space with natural modes of vibration to establish the liner relationship between each order time function coefficient of the distributed load and each order modal excitation. In frequency domain, based on the modal theory each order modal coordinate response of the beam can be identified from the response date of the measuring points on the beam with the Tikhonov regularization method (regularization parameters are determined by the Lcurve method ). Then each order modal excitation and time function coefficient of the distributed load can be identified to rebuild the distributed load on Bernoulli Euler beam structure. The load identification theory proposed in the paper is applicable to all types of loads. The computation simulations show the the universality of the theory and the excellent identification accuracy. Joined random noise, the simulation process shows that the method presented is not sensitive to the measureddatenoise, exhibiting well signaltonoise in load identificantion.