In order to improve the performance in target detection, pulsed Doppler (PD) radar always adopts high pulse repetition frequency (HPRF) signal to obtain wider free clutter areas in frequency domain. However, HPRF will lead to range ambiguity for the detecting target. For the most of current algorithms facing with big computer complexity to solve range ambiguity, a method based on optimal remainder closed-form robust Chinese remainder Theorem (CFRCRT) is proposed, which combines the characteristic and stagger-period model of the PD radar for range estimation of the target. The proposed method can not only accurately reconstruct the true range of the target from the erroneous apparent ranges, but also decrease the computer complexity due to the closed-form solution. Both theoretical analysis and simulation result demonstrate that the method has the advantage in measure precision and real-time performance.