The invention discloses an off-chip capacitor LDO circuit based on the self-adaptive power tube technology.The circuit comprises a control voltage generation unit, a first-stage amplifier, a second-stage amplifier, a frequency compensation unit, a main power tube and an auxiliary power tube.The control voltage generation unit is used for generating control voltage Vctrl; the first input end of the first-stage amplifier is electrically connected with the output end of an LDO, the second input end of the first-stage amplifier is connected with the output end of the control voltage generation unit, the output end of the first-stage amplifier is electrically connected with the input end of the second-stage amplifier, the first end of the frequency compensation unit and the grid electrode of the auxiliary power tube respectively, the grid electrode of the main power tube is electrically connected with the output end of the second-stage amplifier, the main power tube and the source electrode of the auxiliary power tube are connected with a power source, the drain electrodes of the main and auxiliary power tubes and the second end of the frequency compensation unit are electrically connected with the output end of the LDO, and the main power tube is automatically turned on or off according to the load.The off-chip capacitor LDO circuit has the advantages of being low in working voltage, low in no-load current, high in loop gain and wide in output drive range.