In order to reduce the computational complexity of fast motion estimation，and avoid the local minimum problem caused by small diamond search

a motion estimation algorithm based on adaptive search pattern was proposed.This algorithm chose search pattern adaptively depending on SAD changing speed and the temporal relativity in video sequence.Experimental results demonstrated that by using this algorithm

the encoded bit-rate changes within ±0.6% compared with diamond search and hexagon-based search;searching points were reduced to 72%~77% and 83%~86% compared with the diamond search and the hexagon-based search respectively.In the condition of reducing searching points this algorithm avoids local minimum problems.