The invention discloses a high-precision current sampling circuit used in a servo system. The circuit comprises an integrated Hall current sensor circuit, an operational amplifier and a clamping circuit, wherein a current sampling channel of the integrated Hall current sensor circuit is connected with a phase line of a servo motor in series so as to convert a current signal of a phase line into an analogue voltage signal in a proportional relation; the output end of the integrated Hall current sensor circuit is connected with an in-phase end of the operational amplifier; the operational amplifier amplifies the voltage signal and performs level conversion; the output end of the operational amplifier is connected with the clamping circuit; and a clamping circuit protection voltage signal is input into an analog-to-digital conversion unit of a DSP. The high-precision current sampling circuit has the advantages of high linearity and high precision.