The present invention relates to an authentication method and authentication system based on a wearable device. The method includes the steps as follows: a binding step, wherein, an intelligent terminal and the wearable device are pre-bound together; a retrieval authentication step, wherein, the intelligent terminal retrieves whether a bound wearable device exists in the periphery or not during the payment process of the intelligent terminal; performing validity authentication for the wearable device under the condition that a bound wearable device is retrieved; continuously performing payment course after successful authentication, or stopping payment course after a bound wearable device is not retrieved or the authentication is unsuccessful. The present invention can provide the authentication method and authentication system for ensuring payment security.