In assembly occupancies with serried seats distribution, such as cinemas and theaters, the evacuation bottleneck is not only limited to the exit but also in the narrow corridors formed by a large number of seats. These narrow corridors are also an important factor that why people cannot evacuate quickly. This paper observes the evacuation situation of a college theater at the end of movies, and uses BuildingEXODUS to study the influence of seat jumping and corridors’ width altering on evacuation. Studies shows that when the number reaches 20%-60% of the capacity, seat jumping situation during evacuation can improve evacuation efficiency. While the number exceeds 60% or less than 20% of the capacity, the total evacuation time will not change significantly. If the total width of the hallway remains unchanged and the width of each hallway is changed, the exit may reach the state of congestion in advance, which aggravates the congestion at the exit and also has a certain impact on the seat jumping to escape.