  The heavy baryon $\Lambda_b $ is regarded as composed of a heavy quark and a
scalar diquark which has good spin and isospin quantum numbers. In this
picture, we calculate the electromagnetic (EM) form factors of $\Lambda_b$ in
the Bethe-Salpeter equation approach. We find that the shapes of the EM form
factors of $\Lambda_b$ are similar to those of $\Lambda$, which have a peak at
about $\omega=1$, but the amplitudes are much smaller than those of $\Lambda$.
