In this paper, the research results of the relations between the excitation stage of linear ion Bernstein wave (IBW) and the edge ion density fluctuation, the discharge parameters of tokamak and the antenna position in KT-5B tokamak are presented. The experiments show that large edge ion density fluctuation will make it difficult to excite IBW, the ranges of discharge parameters for optimally exciting IBW are consistent with those for normal operation of KT-5B tokamak. We find that for our toroidal current antenna, there may exist two ways of excitation, i.e. direct excitation and excitation through the electrostatic mode conversion process.