The five-dimension searching algorithm is presented for the alignment automation between a laser diode and a single-mode fiber. The searching path and the parameters are discussed in detail. The novel exponential function approximation algorithm for XY plane searching is also presented first. The experimental results with these algorithms are finally presented. It is confirmed that the searching efficiency of the exponential function approximation algorithm is better than the hill-climbing algorithm. The main reason is that the sample points are reduced. Thus the alignment speed is improved notably.