A series fan frame body structure made of different materials includes at least two fans, which are serially connected with each other. The fan frames of the two fans are made of different plastic materials. Accordingly, the excited frequency of the fan is prevented from being close to the natural frequency of the fan frames. Therefore, the vibration frequencies of the fan frames are different from each other so that the co-vibration is reduced to lower the noise. By means of the series fan frame body structure made of different materials, the problem of vibration of the fan is effectively improved.