In　this　paper,　a　novel　transcoding　algorithm　specially　related　to　codebook　gain　conversion　is　proposed　between　AMR-NB　at　7.95kb/s　and　G.729a.　It　can　bypass　the　gain　predictive　process　and　directly　convert　codebook　gain　parameters.　Additionally,　the　new　gain　parameter　conversion　method　can　be　extended　to　the　other　rate　modes　of　AMR-NB　while　transcoding　with　G.729a.　The　experimental　results　show　that　the　quality　of　transcoded　speech　using　the　proposed　algorithm　is　improved　greatly　and　the　computational　complexity　is　reduced　by　85%　compared　with　DIE　(Decode　then　Encode)　method.　A　5ms　look-ahead　delay　is　avoided　as　well.