Abstract:The relationships between the predator and prey's population number were studied with Meta Analysis Method. The results showed as follows. The change of predacious effect varied with the zonal change. The effect in tropics was the biggest, in subtropical zone it was lowest and in temperate zone and frigid zone the medial. The effect in vertebrate classes was bigger than that in inverterate classes.The effect in terrestrial ecosystems was bigger than that in freshwater ecosystems. In general the predator mad...