  We consider backreacted $AdS_5 \times S^5$ coupled with $N_f$ massless
flavors introduced by D7-branes at non-zero temperature. The backreacted
geometry is in the Veneziano limit. The temperature of this system is related
to the event horizon at $r_h$. Dividing one of the spatial directions into a
line segment with length $l$, we will calculate the entanglement entropy
between the two subspaces. We study the behavior near the event horizon, and
finally find that there exists phase transition phenomenon near the event
horizon since the difference between the entanglement entropy of the connected
minimal surface and the disconnected one changes sign.
