The present invention belongs to the body area network technology field, and provides an elliptic curve algorithm-based encryption and decryption method and system. The method comprises the steps of at an acquisition node B, according to the inputted physiological information m, generating a digital signature S, a symmetric encryption ciphertext Fk(m) of the physiological information and a symmetric key K; disassembling the symmetric key base on a binary system, defining K=K1K2, and carrying out the elliptic curve algorithm-based encryption operation by taking the disassembled symmetric keys K1 and K2 as the bases to obtain a recombined key ciphertext CK; sending the data containing the digital signature S, the ciphertext Fk(m) and the recombined key ciphertext CK to an aggregation node A. The method encrypts the physiological information, also enables the efficiency of a hybrid encryption algorithm to be improved.