The period of development of feeding organs is long in paddlefish, Polyodon spathula. Fish feed live food organisms by oral and teeth until 65. 5mm total length. In this stage, oral width and diameter developed quickly, and the size of food organisms is more than 0. 3mm. Gill rakers were not well developed until 65. 5mm of total length. The increasing rate of length and filtering-size of gill rakers is exponential in relation to the total length of fish. The diameter of food organisms which could be filted between gill rakers is more than 0. 1mm which is similar to that of another filt-feeding fish, big head carp (Aristichthysnobilis). The relationship between quantitative characters of feeding organs and change of feeding behaviour was discussed in this paper. Against the total length of paddlifish, the regression analysis of those quantitative characters was also made.