In this work we introduce a power-aware adaptive bus encoding method (or simply PABEM) based on Huffman algorithm. PABEM relies on a change in adaptive Huffman coding algorithm. Ignoring the updating stage of the adaptive Huffman algorithm when a symbol appears for the first time is the modification which we applied in our method. PABEM results in fewer bit transitions of output code words, lower numbers of switching activities and therefore power consumption reduction. We evaluate PABEM using 30 sources (text files with different sizes), and show that it is possible to reduce the numbers of bit transitions and bus power dissipation about 49% and 46% in comparison to adaptive Huffman coding respectively.