Abstract: In this study, differences of acetylcholinesterase and total protein levels which plays very important role in nervous system and some of the related diseases like Alzhemier, Down sendrome, Parkinson in the different age groups in human were investigated. Cholinesterase and total protein levels of 200 healthy people`s blood plasma that are between 7-60 years old were investigated by using spectrophotometric techniques. There was no corelation between plasma cholinesterase activity and age groups. Total protein levels that are 7-12 years old group shows differences than the other groups. Disfunction of food uptake and situation of social cultural cause decreasing the total blood protein in 7-12 years old groups. Meanwhile, this difference in total protein for this group is not enough to predict for some of the disease which to become fact in future. There was no any study on differences of blood plasma acetylcholinesterase and total protein levels in the different age groups in human for Turkey. Because of this specifity this study has original quality and necessary for investigators which study in this area.