The　main　reasons　of　packet　loss　were　described　and　the　related　techniques　of　packet　loss　were　introduced.　Packet　loss　processing　techniques,　which　include　packet　loss　concealment　and　packet　loss　recovery,　were　used　to　recover　and　conceal　the　packet　loss.　And　the　aim　of　packet　loss　prevention　was　to　prevent　network　congestion　in　order　to　reduce　the　packet　loss　rate.　In　addition,　the　current　situation　and　trend　about　VoIP　were　given　and　discussed.