For VLSI design in deep submicron technology, the bus energy reduction becomes more and more important. In this paper, we modify the bus-invert coding method to maximize the power consumption reduction of data bus. Unlike the conventional scheme in which the whole bus lines are considered for bus-invert coding, our scheme partitions the bus lines into several sub-buses and each partitioned sub-bus is coded independently by bus-invert coding method. For an 8-bit data bus the bus-invert coding method can reduce at least 25% power consumption, while the traditional bus-invert method is 18.75 %.