The recent development of high-entropy perovskites has demonstrated their tremendous promise for various applications. To meet the expanding needs for extreme environment applications, however, the critical properties of high-entropy perovskite at high pressure remain to be disclosed. In the present work, an A-site high-entropy perovskite (Nd0.2Li0.2Ba0.2Sr0.2Ca0.2)TiO3 was synthesized. High-pressure investment on the phase stability, dielectric properties, and bandgap was conducted using diamond anvil cell combined with comprehensive in-situ measurements. The results reveal that (Nd0.2Li0.2Ba0.2Sr0.2Ca0.2)TiO3 remains the perovskite structure at the pressure up to similar to 15 GPa. The grain resistance exhibits an exponential decrease with the increasing pressure, whilst an unusual change of the grain boundary resistance was observed at similar to 7 GPa. Furthermore, (Nd0.2Li0.2Ba0.2Sr0.2Ca0.2)TiO3 shows a slight increase of the bandgap upon compression. Our multifaceted approach provides a comprehensive understanding of the high-pressure behavior of high-entropy perovskite, offering valuable insights for the design and optimization of advanced functional materials for high-pressure environments.