Abstract: A portable plug and play collision avoidance device includes a processor, a positioning receiver, and a communication module. The communication module is electrically connected with the processor for transmitting message packets to other carriers or receiving message packets from other carriers. The portable plug and play collision avoidance device further includes a transmission interface, such that in case the processor determines that the carrier is located at a collision trajectory of another carrier, the processor will output a notice signal transmitted, through the transmission interface to a receiving interface of the carrier; or through the transmission interface to a receiving interface of a mobile device so as to achieve the purpose of early warning. As such, an instant location information and trajectory warning can be provided to various kinds of displays so as to change the user's travelling path instantly, and to secure the user's safety.