In this paper,by using some view points of non-linear dynamics,for example,sensitivity to original condition,fractal dimension,bifurcation,chaos prediction size of earthquake process,and so on,we discussed the modulation triggering,common dimension time and area and inlay modulating of small earthquakes.Author also analyzes some anomaly phenomena of the Gonghe earthquake in Qinghai province in 1990.The analysis has certain reference value to understanding precursory complexity of earthquake.