The implicit approach can be used to efficiently model realistically deformable objects for large constraints such as stiffness or time. In soft bodies with pressure forces, models are composed of mesh points connected by springs and applied with pressure forces. System parameters such as spring constant, damping constant, etc. are defined to describe the behaviors of the deformable objects. Since the simulation of soft bodies with pressure force fails when the constraints are large, this paper proposes the method to solve this problem by using the implicit integration method for soft bodies with particular force. The results show that our method can realistically simulate the soft bodies when large constraints are applied.