  BaNi$_2$As$_2$, with a first order phase transition around 131 K, is studied
by the angle-resolved photoemission spectroscopy. The measured electronic
structure is compared to the local density approximation calculations,
revealing similar large electronlike bands around $\bar{M}$ and differences
along $\bar{\Gamma}$-$\bar{X}$. We further show that the electronic structure
of BaNi$_2$As$_2$ is distinct from that of the sibling iron pnictides.
Particularly, there is no signature of band folding, indicating no collinear
SDW related magnetic ordering. Moreover, across the strong first order phase
transition, the band shift exhibits a hysteresis, which is directly related to
the significant lattice distortion in BaNi$_2$As$_2$.
