In the actual network, network delay jitter even with a long tail, not only causes coordinates oscillation, but also seriously affects the stability of IP network coordinate system and accuracy of time delay prediction, so it is necessary to preprocess the measured time delay to avoid the performance of IP network coordinate system affected by “distortion delay”. This paper introduces and analyses the characteristics of the existing delay preprocessing algorithms of Δ-filter and MP-filter, then puts forward another delay filter algorithm called RPE-filter. Comparing experiment shows that RPE-filter can not only filter the time delay polluted by random delay, but also can smooth fluctuation of the delay curve, even more can real-time reflect the changes of network topology, and the most important is that its absolute error accumulation is obviously less than Δ-filter and MP-filter.