Non-Obstructive Particle Damping (NOPD) is a new damping technique which is based on traditional particle damping and impact damping technique. NOPD Structure has a good effect on decreasing sound and vibration. A new improved algorithm based on the endochronic theory is researched in the paper. Response calculation by the algorithm and tests for NOPD beam have been done in conditions of one, two and three holes filled with tungsten particles. Results show it feasible to calculate the response of NOPD structure by the improved algorithm, which affords an effective analysis method for engineering application of NOPD technique.