Disclosed are a data security processing method, apparatus and system. The method comprises : acquiring an encryption key when a first electronic device using the method detects a communication connection between the first electronic device and a second electronic device; encrypting target data by using the encryption key; and finally, securely transmitting the encrypted data to the second electronic device for storage. Accordingly, when the present application is used, by encrypting collected physiological data of a user, a wearable medical health device can securely transmit collected data at a high privacy level to an external electronic device (for example, a mobile phone of the user) for storage, thereby implementing security protection on data with user privacy.