Topological materials get extensive attention in last three decades. HgCr2Se4 is one of those materials being a Weyl semimetal which is induced by time-reversal symmetry breaking. Magnetic order is proposed to be a necessary condition for the material being a Weyl semimetal. However, experimental results concerning the magnetic ground state and exchange couplings, which is crucial for understanding the Weyl physics, is still lacking. Therefore, it is necessary to do detailed measurements to get the whole picture magnetic excitations using inelastic neutron scattering.