This article counted and analyzed the duration，spatial distribution，form，range，type and reliability of abnormities based on the abnormity observation of earthquake precursors of 24 mezzo forte earthquakes at Tanlu cross-fault and its bilateral areas such as Shandong，Liaoning， Hebei，Jiangsu，Jiangxi provinces from 1966 to 2005． Results showed that: (1) For M1. 7 and M6． 0 earthquakes， medium-term abnormities occurred most often， short-term abnormities occurred sometimes， and impending earthquake abnormities occurred rarely． For M5. 0 earthquakes，short-term abnormities occurred most often，impending earthquake abnormities occurred sometimes and medium-term abnormities occurred rarely． ( 2 ) Precursory abnormities are periodical，part of the medium-term and short-term abnormities showed short-term and impending earthquake abnormities during its development． ( 3 ) The development of precursors showed prospective synchronism; the closer to earthquakes，the more changes of directions of abnormities． (4) Abnormities mainly occurred within 100km2 distance of the epicenter． It showed relative centrality in space and the shorter the distance of epicenter，the higher the abnormity to total observation ratio． ( 5 ) The space distribution and the structure trend of abnormities were relatively correlated． It showed good interdependency with the structure． ( 6 ) There was no significant correlation of the duration of the abnormities and the distance of epicenter． (7) The higher the magnitude of the earthquake，the bigger the range of the abnormities with the same observation approach． (8) Fluid subject showed the most abnormities，followed by deformation and electromagnetism subjects． ( 9 ) For all different subjects，medium-term and short-term abnormities made up the majority and short-term and impending earthquake abnormities were the minority． ( 10 ) For fluid，deformation and electromagnetism subjects，the relative reliable abnormities were about double the reliable abnormities．