  We report the high resolution photoassociation (PA) spectroscopy of a
$^{87}Rb$ Bose-Einstein condensate (BEC) to excited molecular states near the
dissociation limit of $5P_{1/2} +5S_{1/2}$ by optical Bragg scattering. Since
the detection of optical Bragg scattering in BEC has a high signal-noise ratio,
we obtain the high resolution PA spectrum of excited molecular states in the
range of $\pm1$ GHz near the dissociation limit of $5P_{1/2} +5S_{1/2}$. We
compare the results with the conventional method of trap loss and show that the
results agree each other very well. Many interesting phenomena of excited
molecular states are observed, such as light-induced frequency shift and the
anomalous strong bound molecular lines at the atomic transition from
$|F=1\rangle$ to $|F^{\prime}=2\rangle$. The observed excited molecular states
in the range of $\pm1$ GHz near the dissociation limit of $5P_{1/2} +5S_{1/2}$
are never reported before, which will help to further improve the long range
bound state models near the dissociation limit.
