The　CIOs　of　many　SMEs　take　a　wait-and-see　attitude　towards　IaaS　public　cloud.　Their　greatest　concern　is　whether　IaaS　public　cloud　access　can　really　reduce　cost.　This　paper　analyzes　and　compares　the　cost　of　self-built　server　of　SMEs　and　accessing　three　public　cloud　providers,　and　factors　except　for　price　that　should　be　taken　into　account　in　the　hope　of　providing　better　reference　for　informatization　construction　of　SMEs..　©　2014　Trans　Tech　Publications,　Switzerland.