The invention relates to a low-voltage-difference linear stabilized-voltage circuit, which comprises a power-supply end, a reference-voltage end, an output end, a load, a grounding end, a fast-channel circuit and a slow-channel circuit, wherein the fast-channel circuit is connected between the power-supply end and the load and is used for adjusting a voltage value output by the output end, the slow-channel circuit is connected between the power-supply end and the load and is used for stabilizing the voltage value output by the output end, the fast-channel circuit and the slow-channel circuit are together connected with the output end, the slow-channel circuit is connected with the reference-voltage end, the fast-channel circuit comprises a first field-effect transistor and a control subcircuit which is connected with the first field-effect transistor, and the slow-channel circuit comprises an operational amplifier which is connected with the reference-voltage end, a first resistor which is connected with the operational amplifier, a second resistor which is connected with the first resistor and the first field-effect transistor. The invention also provides a low-voltage-difference linear stabilized-voltage system. The low-voltage-difference linear stabilized-voltage circuit and the low-voltage-difference linear stabilized-voltage system have simple structures, the power consumption is reduced, and the output precision is ensured.