The invention discloses a high-precision reference voltage source circuit.The high-precision reference voltage source circuit comprises a start circuit, a PTAT current generating circuit and a reference voltage generating circuit which are electrically connected in sequence.The start circuit is used for generating a start signal of the beginning of the circuit, so that the whole PTAT current generating circuit and the reference voltage generating circuit are completely opened, and then the start circuit is automatically closed; the PTAT current generating circuit is used for generating reference current forming a proportionality coefficient with positive temperature.The reference voltage generating circuit is used for generating high-precision reference voltage irrelevant to temperature.The high-precision reference voltage source circuit is characterized in that two positive temperature coefficient compensation items are embedded on the basis of traditional positive temperature coefficient mutual compensation during reference voltage generation, the regulating range of the reference voltage is effectively widened, errors brought by single-item regulation are efficiently compensated, and finally the precision of the reference voltage is effectively improved.The structure of the circuit is greatly simplified, power consumption is reduced, and the capacity of resisting high-frequency power source ripple interference is improved.