It has recently been pointed out that,under certain conditions,the energy of particles accelerated by black holes in the center-of-mass frame can become arbitrarily high.In this paper,we study the collision of two particles in the case of four-dimensional charged nonrotating,extremal charged rotating and near-extremal charged rotating Kaluza-Klein black holes as well as the naked singularity case in Einstein-Maxwell-dilaton theory.We find that the center-of-mass energy for a pair of colliding particles is unlimited at the horizon of charged nonrotating Kaluza-Klein black holes,extremal charged rotating Kaluza-Klein black holes and in the naked singularity case.