  We derive the second-order post-Minkowskian solution for the small-deflection
motion of test particles in the external field of the Kerr-Newman black hole
via an iterative method. The analytical results are exhibited in the coordinate
system constituted by the particles' initial velocity unit vector, impact
vector, and their cross-product. The achieved formulas explicitly give the
dependences of the particles' trajectory and velocity on the time once their
initial position and velocity are specified, and can be applied not only to a
massive particle, but also to a photon as well.
