The vulnerability of an urban rail transit (URT) network can be effectively reduced by allocating protective resources (PRs) to stations and links before disruptions occur. However, few studies have reduced the vulnerability of a URT network by allocating PRs. Moreover, existing studies on reducing the vulnerability of a URT network rarely consider the extent and severity of unforeseen disruption. To address this gap, a scenario model that aims to reduce the vulnerability of a URT network experiencing disruption by allocating PRs is developed taking account of the area and severity of the disruption. Numerical experiments conducted on the Chengdu subway network reveal that the weighted average travel time between stations and the total number of passenger trips increases and decreases on average by 0.38% and 0.001%, respectively, when the normal operation of any station is affected by a disruption. The network’s growth ratio of weighted average travel time between stations and loss ratio of passenger trips are reduced by 43.26% and 46.61%, respectively, when a total of 479 PRs are allocated to 15 stations. Finally, this study discusses the impact of parameters on the effectiveness of the vulnerability reduction in the proposed model.