In 3-quart saucepan, cook pasta as directed on package 2 minutes. Add green beans; return to boiling. Cook 8 to 10 minutes or until pasta and beans are tender. Drain; return to saucepan.
Meanwhile, in 10-inch nonstick skillet, mix milk and flour until smooth. Heat to boiling over medium-high heat, stirring constantly. Cook and stir until thickened. Remove from heat.
Stir in cheese sauce and sausage until cheese sauce is melted. Add cooked pasta and beans; toss gently to coat. Reduce heat to medium-low; cook until thoroughly heated.