Abstract: In this paper, the problem of deriving the transfer functions of stationary secondorder linear distributed parameter systems is studied. Firstly, a piece-wise method is used to get the approximation of the system, and the transfer functions of the system are then developed under two different sorts of boundary conditions. Under the first condition the transfer functions are formed accordrng to the inherent property of a secondorder differential equation, while under the second they are expressed as the final results of a set of recurrence formulas.