The present application provides a method and device for determining input information, and relates to the field of a wearable device. The method comprises in response to a first part of a body of a user executing an action, acquiring target blood-flow information about the first part or a second part that corresponds to the first part; and determining input information according to the target blood-flow information and reference information. According to the method and device, the body of the user is used as an input interface, to cause an interaction area to be increased, which helps to improve input efficiency and user experience.