The　Viterbi　algorithm　(VA)　is　a　maximum　likelihood　(ML)　decoder　for　convolutionally　encoded　data.　A　more　advanced　decoding　method　is　list　Viterbi　algorithm　(LVA)　which　produces　the　list　of　the　L　best　output　sequences　over　a　certain　block　length　in　decoding　a　terminated　convolutional　code.　The　constrained　Viterbi　algorithm　(C-VA)　is　a　method　proposed　to　makes　full　use　of　the　information　of　the　known　correctly　decoded　bits.　In　this　paper,　advantages　of　these　two　methods　are　completely　exploited　together　in　image　transmission.　Simulation　results　show　that　the　decoding　complexity　can　be　reduced　dramatically　and　the　performance　can　be　improved　greatly　by　using　constrained　list　Viterbi　algorithm　(CLVA).