With　the　rapid　development　of　electronic　information　technology　and　internet,　e-commerce　has　been　a　new　means　of　market　transactions,　which　take　a　huge　advantage　in　market　for　its　convenience　and　openness　in　information　acquisition,　transmission,　and　communication　and　transaction　costs.　However,　the　moral　hazard　and　adverse　selection　resulting　from　information　asymmetry　induce　imbalance　between　the　interests　of　both　parties,　reduce　the　efficiency　of　resource　allocation　and　violate　the　fairness　and　justice　of　social　development.　Therefore,　in　order　to　promote　and　facilitate　the　e-commerce,　this　paper　arms　to　analyze　the　effects　and　causes　of　the　information　asymmetry　and　propose　relevant　measures.　©　2011　IEEE.