Operational readiness and mission availability are two important standards in equipment supportability. To evaluate these two standards, an improved particle swarm optimization (PSO) algorithm to solve the mixed integer programming (MIP) problems has been developed. The augmented Lagrange multiplier method is employed to deal with the constraints, and special update strategy employed to restrict the swarm particles to lies only in integer positions. Tests on the two former mathematical models have verified the effectiveness of the proposed mixed technique, and it can be easily applied to other mixed integer programming with Constraint problem.