The invention provides the pressure compensating circuit of the brushless motor device without sensing direct current. It can be used to compensate the motor armature end pressure of the said motor device. The driving circuit of the motor device can have the three phases power supply output, each phase output can connect the one compensating circuit equally, each pressure compensating circuit includes one consulting pressure, one resistance organ, one diode organ, one differential amplifier, one processor. The two ends of the resistance organ connect the consulting pressure and the anode of the diode component partly, the cathode of the diode component connects the one phase of the three phases power output, the two output ends of the differential amplifier connect the two ends of the resistance component partly, the processor can take the signal outputted from the differential amplifier and account, so the compensating pressure is outputted.