  High resolution angle resolved photoemission measurements and band structure
calculations are carried out to study the electronic structure of BaMnSb$_2$.
All the observed bands are nearly linear that extend to a wide energy range.
The measured Fermi surface mainly consists of one hole pocket around $\Gamma$
and a strong spot at Y which are formed from the crossing points of the linear
bands. The measured electronic structure of BaMnSb$_2$ is unusual and deviates
strongly from the band structure calculations. These results will stimulate
further efforts to theoretically understand the electronic structure of
BaMnSb$_2$ and search for novel properties in this Dirac material.
