The invention discloses a method for testing sound propagation experiments of rai car structures under carload semi-anechoic room environment, and belongs to the technical field of acoustic experiments. According to the method, a carload semi-anechoic room which is enough to contain a tested car model is constructed according to an overall dimension of a train; a single carriage of a rail car under a prepared state is put in the carload semi-anechoic room; and structural vibration noises generated to passenger room carriages by bogie noises and transfer paths of the structural vibration noisesare analyzed by utilizing an existing transfer path analysis method for structural vibration noise components. According to the method, influences, on test results, of low-frequency noises in structural sound propagation test site environment are avoided, and a technical acceptance standard for a free field deviation value of the carload semi-anechoic room and optimum position parameters, relative to specific local parts, of noise sampling points in the passenger room carriage are definitely given, so that structural sound propagation experiments can obtain optimum experiment results.