  We calculate the metric for a self-gravitating and collapsing infinitely-thin
spherical shell under the theory of post-Newtonian approximation, and
successfully recover the shell's energy-momentum tensor from the achieved
metric. The post-Newtonian dynamic equations of the test particles inside and
outside the shell are achieved respectively. It is demonstrated that the radial
motion of the spherically-symmetric system can contribute to the second
gravitational potential and the gravitomagnetic field, inducing the
time-dependent gravitational effects.
