State estimation is the base of distribution network application software. Enough measurement is the base of observation. By taking into account the real-time measurements with low redundancy and most of them are current measurements, based on the relationship among the distribution network running parameters, the method getting active and reactive power measurements using electric current measurement is proposed. Using the method can add many pseudo measurements. According to radial operation feature of electric distribution network, the feeder tree is formed, and the linked list is used to keep the relationship among the elements in the distribution network. The forward-backward sweep method is adopted in adding pseudo measurements. The matching current equations in the sense of optimal estimation and its systematic solution are deduced. The result of an actual system shows that the proposed method is feasible. The method proposed can satisfy the real-time application demand of the distribution system.