A connection interface switching device for multiple portable devices provides a communication channel between an I/O peripheral set and for a plurality of portable devices which are bundled with a default control program installed in the portable devices, and switches among the portable devices to establish a communication channel selected between one portable device and the I/O peripheral set according to a switch instruction generated by the default control program of the portable device. The connection interface switching device includes plural I/O ports, a controller, a memory module, a storage module and an I/O peripheral port, and an origin of the computer signal is controlled and switched to achieve the effect of sharing the same I/O peripheral set among multiple portable devices through the communication channel.