  The time-integrated polarization degree (PD) at prompt optical band of
gamma-ray burst (GRB) was predicted to be less than $20\%$, while the
time-resolved one can reach as high as $75\%$ in photosphere model.
Polarizations in optical band during GRB prompt phase had not been studied
under framework of the magnetic reconnection model. Here, a three-segment power
laws of the energy spectrum is used to reconstruct the Stokes parameters of the
magnetic reconnection model. The multi-wavelength light curves and polarization
curves from the optical band to MeV gamma-rays in GRB prompt phase are studied.
We found depending mainly on the jet dynamics there is a long lasting high PD
phase at all calculated energy bands for the typical parameter sets. The
time-resolved PD could be as high as $50\%$, while the time-integrated one is
roughly $17\%$) in optical band. It can reach $60\%$ for the time-resolved PD
in X-rays and the time-integrated one is around $(30-40)\%$. The polarization
angle (PA) evolution is random in both optical and gamma-ray bands for the
photosphere model, while it is roughly a constant in the synchrotron models.
Therefore, future time-resolved PA observations in the prompt optical or
gamma-ray band could distinguish between the photosphere and the synchrotron
models.
