Abstract: Objective To study the influence of fluorosis due to food pollution on learning and memory of offspring rat and its possible mechanism.Methods Thirty two SD rats were randomly divided into control group and high fluor ideex posed group.High fluoride exposed group was fed with the cornpolluted in drying processes with burning coal containing high level off luoride.After six months,the rats were mated and their filial generations atage of 30 days were examined.The ability of leaning and memory was measured with Morristest and cholinesterase activity was detected with photometric method after expermient.Results The mean value of escapelatency of off spring rats in high fluoride exposed group(9.242±5.852s)was significantly prolonged compared to that of the controls(4.948±2.698s P<0.01);the significantly decreased numbers of crossing the platform and the declined tmie of staying the plat form were found in off springrats with high fluoride exposure(3.040±1.968 tmies,23.070±5.427s)compared to that of controls(4.440±2.615 tmies,27.640±7.344 s;P<0.05 and P<0.01);the activity of the choline sterase in the brain of off spring rats exposed to higher fluoride was obviously decreased in comparison with controls(P<0.01).The correlation analysis showed that there were a negative correlation between the cholineste rase and the escape latency and a positive correlation between the choline sterase and numbers of crossing the platform and the tmie of staying the plat form.Conclusion Fluo rosis can cause decreased ability of learning and memory of off spring rats,in which the mechanism might be related to the decreased activity of choline sterase.