A portable device for controlling an external electrical adjustable apparatus is provided. The portable device has a case, a signal transmitter connected to the electrical adjustable apparatus, a tilt sensor sensing a tilted angle and a controlling operation, a memory storing a threshold angle and a processor. The processor generates a controlling signal according to the controlling operation, and transmitting the controlling signal to an electrical adjustable apparatus for making the electrical adjustable apparatus raise/lower. The processor further determines that the electrical adjustable apparatus has collision when receiving a controlling signal used to control the electrical adjustable apparatus and the tilted angle is not less than the threshold angle, and sends a stopping signal to the electrical adjustable apparatus via the signal transmitter for making the electrical adjustable apparatus stop raising/lowering when determining that the electrical adjustable apparatus has collision.