Using the method of natural orthogonal function expansion, the authors analyzed the temporal variations of the seismic energy fields around the epicenter and along the Yushu Fault zone before Yushu M 7.1 Earthquake,  Qinghai Province on Apr.14 in 2010.The anomaly of time factor in primary typical fields along Yushu Fault Zone all appeared in 2～3 years before the main shock, which probably represented that the anomaly of the earthquake preparation area fields also appeared early. The abnormal features of the time factors of the typical fields were similar to the results about the energy fields in the former work.