Abstract: In order to study the influence of temperature distribution on the sound transmission characteristics in the pipe array structure, different temperature fields including the periodic non-uniform temperature fields are constructed according to the actual working conditions of nuclear power plant, and the finite element method is used for numerical simulation. The results show that :(1) the temperature distribution changes the width of the "gap" and the location of the center frequency in the sound transmission spectrum of pipe array, and the effect of temperature change on higher frequency locations is greater than that on lower frequency locations in the same medium; (2) in the condition that the temperature difference of 10℃ is the same, the average sound velocity of water is 1 653 m·s^-1 and the average sound velocity of saturated water vapor is 522.5 m·s^-1, the band gap width and the center frequency location change greatly when the medium is water, that is, the sound transmission spectrum of pipe array in the medium with large sound velocity is more sensitive to the temperature change. (3) When the temperature difference is less than 10℃, there is little difference between the two spectra before the first central frequency of 23 996.1 Hz in the non-uniform temperature field with periodic variation and in the uniform temperature field, and a significant difference will appear after the first band gap. The research results provide a theoretical basis for the improvement of acoustic detection method in nuclear power plant.