  We have studied a flavor-changing toppion production process $e^{+}e^{-}\to
t\bar{c}\Pi^{0}_{t}$ in the topcolor-assisted technicolor(TC2) model. The
studies show that, with high centre of mass energy in TESLA collider, the
production cross section of $e^{+}e^{-}\to t\bar{c}\Pi^{0}_{t}$ is at the order
of magnitude 0.1 fb in most parameter regions of TC2 model and a few tens
events of toppion can be produced each year. The resonance effect can enhance
the cross section to a few fb when toppion mass is small.
  With clean background, the toppion events can possibly be detected at TESLA
collider. On the other hand, we find that there exists a narrow peak near
$m_t-m_c$ in the toppion-charm invariant mass distribution which could be
clearly detected. Therefore, such a toppion production process $e^{+}e^{-}\to
t\bar{c}\Pi^{0}_{t}$ provides a unique chance to detect toppion events and test
the TC2 model.
