By using penetration experiment and numerical simulation methods， the damage characteristics of the multilayer thin steel target penetrated by reactive materials （RMs） under hypervelocity impact condition was investigated. The two-stage light gas-gun was used to study the damage mode of PTFE/Al based RM and Al-based all-metal RM to multilayer thin steel target， the influence of material type and penetration velocity on damage effect is presented. The results show that， compared with inert metal， both of RMs have lateral damage enhancement effect on multilayer thin steel target， which the broken hole size of the second layer can reach more than 4 times of the bullet dimeter （BD）. The AUTODYN numerical simulation software was used to prove the efficiency of the RM parameters and then the damage effect numerical simulation of RMs were carried out. The results show that the damage characteristics of PTFE/Al-based RM and Al-based all-metal RM to multilayer thin steel target can be described by J-C model combined with Lee-Tarver model and J-C model combined with Shock equation respectively. Additionally， the phenomenon that the increase in penetration speed can hardly improve the lateral damage enhancement effect of the PTFE/Al-based RM but can significantly improve that of the Al-based RM to the multilayer steel target， which is mainly due to the difference in energy releasing mechanisms between two kinds of RMs.