  The two-photon-exchange (TPE) effects in the process $e^+e^- \rightarrow
\pi^+\pi^-$ at large momentum transfer are discussed within the perturbative
QCD (pQCD). The contributions from the twist-2 and twist-3 distribution
amplitudes (DAs) of pion are considered in the estimation. Different with the
results under the one-photon-exchange (OPE) approximation, the TPE effects
result in an asymmetry of the differential cross section on the scattering
angle. The precise measurement of this asymmetry by the further experiment is
an precise test of pQCD at large momentum transfer. The time-like
electromagnetic form factor of pion at the leading order of pQCD is
re-discussed and the comparison of our results with those in the references are
presented.
