Abstract: This paper presents the computing formula and method of general information fractal and studiesNorth China, Southern Yellow Sea and its cast, Sichuan-Yunnan, Gansu-Qinghai-Ningxia, andXinjiang areas where there are more earthquakes except Qingzang highland where the metworks of stations are quite few and have no observational ability for moderate and small earthquakes, The resultshows that there is a relatively obvious fractal drop process before some main earthquakes;there are certain fractal drop anomalies before some moderately strong earthquakes in North China areal there areobvious fractal drops after strong earthquakes in high scale value areas of spatial information fractal inXinjiang, Gansu-Qinghai-Ningxia regions, but there are no fractal drops before earthquakes, thereare precursory fractal drops before earthquakes in all low scale value areas and they recovered afterearthquakes. The precursory drop of time fractal is more obvious than spatial fractal. When tested byXu's R value, R_s=0.386, R_t=0.83, all exceeding the marked level.