The disclosure provides a method for determining a posture of a user, a host, and a computer readable medium. The method includes: detecting a relative position between a first wearable device and a second wearable device; and in response to determining that the relative position between the first wearable device and the second wearable device satisfies a predetermined relative position, determining the posture of the user at least based on the relative position between the first wearable device and the second wearable device.