According to the difficulty of measuring low amplitude current accurately， an electronic current transducer applied to low amplitude current measurement is studied. On the base of system's characteristic， the phase error caused by system is analyzed and calculated， then according to the result and the characteristics and shortage of anciently phase compensation circuits， a new phase compensation circuit is designed， which based on all pass filter circuit， namely adopted two series one rank all pass filter circuits to compensate small phase error，and the imitation and examination result is given. The result indicates that this compensation project has well phase compensation effect， and also can make the system meet 0.2 level of international criterion.