A dual mode communication device comprises a first mode chip, a second mode chip, a switch, a first headphone jack, and a second headphone jack. The first headphone jack is electronically and selectively connected to the first mode chip or to the second mode chip through the switch. The second headphone jack is electronically connected to the second mode chip. The dual mode phone can simultaneously establish two voice communications with two other communication devices using the first mode chip and the second mode chip by respectively transmitting voice signals of the two voice communications through the first headphone jack and the second headphone jack.