A power coupling device with detection and power adjustment function includes at least one detection unit, at least one switch unit, at least one coupling unit, at least one amplification unit, at least one comparison unit and at least one logic unit. The detection unit serves to receive a first operation power and a second operation power. The coupling unit serves to couple the first and second operation powers for a power output end to output a regulated output power. The comparison unit serves to compare to generate a first comparison result and a second comparison result. According to the first and second comparison results, the logic unit logically judges to generate a triggering signal for controlling the switch unit to turn on or turn off the switch unit so as to adjust the power of the regulated output power.