  A light bridge is a magnetic intrusion into a sunspot, it interacts with the
main magnetic field and excites a variety of dynamical processes. In the
letter, we studied magnetic connectivity between a light bridge and coronal
loops rooted at the sunspot. We used the data of the Atmospheric Imaging
Assembly onboard the Solar Dynamics Observatory (SDO) to study the features of
sunspots with light bridges. It is found that if a light bridge anchors at the
umbra-penumbra boundary, the coronal loops could not be formed around the
anchoring point. If the a light bridge become detached from the penumbra, the
coronal loop starts to form again. The vector magnetogram provided by the
Helioseismic Magnetic Imager onboard SDO shows that the anchoring region of a
light bridge usually have an accompanying opposite minor-polarities. We
conjugate that the magnetic field line could connect to these opposite
polarities and form short-range magnetic loops, and therefore, coronal loops
that extend to long-range could not be formed. A model of light bridge is
proposed to explain the magnetic connectivity between a light bridge and the
coronal loops. This model could explain many physical processes associated with
light bridges.
