The dominant operation of the Elliptic Curve Cryptgraphy is to compute the scalar multiplication(kP).The Double-Base Number System(DBNS) gives fewer non-zero digits than binary representation or NAF. This is why it is a very efficient method to compute the scalar multiplication. But existing research uses the Greedy algorithm to generate DBNS representation from scalar k, and it has a problem not to be able to generate best representation for efficient scalar multiplication, We propose an improved Greedy algorithm, which generates a suitable DBNS representation for efficient scalar multiplication.