The cryptographic device generates a large amount of physical information such as electromagnetic，energy consumption，heat，etc. during encryption and decryption. The attackers use these physical information to perform a side channel attack on the cryptographic device and steal the key of the cryptographic device. In the case of a traditional simple power analysis attack of elliptic curve cryptography algorithm，the attacker recovers the key by manually identifying similar modules in the power consumption data of the double point calculation. But this way results in low attack efficiency and low attack accuracy. This paper proposes the SPAMD algorithm based on the time series of motif discovery. The algorithm realizes the automatic recognition of similar modules in the power consumption data of the double point calculation，and completes the conversion of the attack mode from manual recognition to automatic recognition. Experiment results show that SPAMD attacks have a significant improvement in efficiency and accuracy.