The present invention refers to a wearable light-emitting device that can be used for safety warnings, cheering, and light show performing. The invention also refers to a control method that allows the wearer to perform different commands by waving her/his hand in left or right, up or down, forward or backward directions. In addition, the control method allows the wearer to turn off/on the light and change its color with simple actions such as closing and opening her/his hand. Furthermore, the invention allows the wearer to easily handle other objects or perform grasping tasks while wearing this device.