Zhang et al. reported[1] that they conducted lightgas gun experiments to study the behaviour of dense hydrogen/helium gas mixtures, and the optic radiations emanating from the multi-shock reverberations between the iron base-plate and the single crystal sapphire window were recorded successfully up to the 10th reflection, and 9 shock compression data points were thus obtained. Their gas mixture even reached a high pressure beyond 100 GPa. This comment put forward a few questions on their experimental data reported in Fig. 4 in Ref. [1].