  The measurement of the $\sigma(e^+e^-\rightarrow \pi^+\pi^-)$ cross section
allows to determine the pion form factor $| F_\pi |^2$ and the two pion
contribution to the muon anomaly $a_\mu$. Such a measurement has been performed
with the KLOE detector at $DA\Phi NE$, the Frascati $\phi$-factory.The
preliminary results on the combination of the last analysis (KLOE12) with two
previous published (KLOE08, KLOE10) will be presented in the following.
