The　problem　of　high　energy　consumption　is　becoming　more　and　more　serious　due　to　the　construction　of　large-scale　cloud　data　centers.　Detecting　and　switching　underloading　hosts　into　sleep　mode　is　the　key　approach　to　reduce　energy　consumption.　In　this　paper,　we　propose　Minimum　Utilization　with　Threshold　algorithm　to　reduce　energy　consumption　and　VLA　violation.　We　use　the　simulator　CloudSim　in　our　experiment　with　our　algorithm　and　have　a　significant　reduction　on　both　energy　consumption　and　SLA　violation　based　on　our　data.