  We study the pion electromagnetic form factor in the modulus squared
dispersion relation, and do the model independent extraction of the most
important nonperturbative parameters in pion light-cone distribution amplitude.
The motivation of this work is the recent measurement of timelike form factor
in the resonant regions, which makes up the piece lacking solid QCD-based
calculation. With the perturbative QCD calculation up to next-to-leading-order
QCD corrections and twist four level of meson distribution amplitudes, we
obtain the chiral mass of pion meson as $m_0^\pi(1 \, {\rm GeV}) =
1.31^{+0.27}_{-0.30} \, {\rm GeV}$. More accuracy measurement of the timelike
form factor are desirable to help us to determine the lowest gegenbauer moments
in pion distribution amplitudes with the data-driven dispersion relation method
developed in this work.
