SM2 algorithms are commercial elliptic curve public-key algorithms, which are released by Chinese Cryptography Administration and similar to ECC. Traditional cryptographic algorithms always have security flaws. Attackers often attack on security weaknesses of algorithms and analyze the secret-key, which poses great threat to cryptographic systems and peoples property. There are various kinds of attacks, such as power attack, fault attack and electromagnetic attack. Among these attacks, power attack is the most traditional one, which has many advantages such as small secret-key searching space and high analysis efficiency. Usually, power attack utilizes the power leakage during operation processes of cryptographic algorithms, acquires power waves and retrieves the secret key. In order to resist power attack and enhance the security of SM2 algorithms, this article learns from elliptic curve cryptography algorithms, applies the atomic concept into SM2 and proposes a novel atomic algorithm. According to theoretical comparison between the proposed algorithm and other former algorithms, it shows that the proposed algorithm saves 27.4% of computation in comparison to double-and-add always algorithm. Besides, it has less computation amount than other atomic algorithms. Furthermore, implementation has been fulfilled on SAKURA-G FPGA board. Simulation results demonstrate that the proposed algorithm can resist simple power attack successfully.