The present invention discloses a portable image monitoring and identifying device suitable for monitoring an activity in the image and/or identifying image contents and when an image activity and/or an identified image content triggers certain preset event, a command or trigger signal can be sent out for controlling other external devices to act and/or send out a message to the user. The portable device includes an image input unit for inputting an input video, a main processor unit for executing functions of processing image data, detecting activity and triggering event, a memory unit for storing an operation data of the main processor, an input port for connecting with an input device so as to support the necessary operation by the user, and a control output port for outputting the command or trigger signal described above so as to control other external devices connected to the control output port to act.