Scalar multiplication is a very time consuming process, thus plays an important role in elliptic curves digital signature algorithm (ECDSA). To speed up the scalar multiplication process, in this paper, we propose a novel scheme, different from both principles mentioned above, to accelerate the execution of scalar multiplication by elaborately generating a random scalar in ECDSA. Experimental results illustrate that the proposed method can greatly reduce the number of point addition operations in scalar multiplication compared with other existing methods.