Abstract: Objective To explore the correlation between the severity of Alzheimer's disease (AD) and the levels of serum copper,iron and zinc. Methods Total 165 subjects were selected and divided into the healthy group,and mild,moderate and sever dementia group according to the scores of Mini-Mental State Examination (MMSE),which defined scores of 21 to 26 as mild dementia,10 to 20 as moderate dementia,0 to 10 as sever dementia.The levels of serum copper,iron and zinc of all the subjects were tested. Results The levels of serum copper of the moderate and sever groups were statistically higher than those of the healthy group and mild group,while the levels of serum iron and zinc of all dementia groups were statistically lower than those of the healthy group which suggested there's a decrease of serum iron and zinc in AD patients.There's negative correlation between the scores of MMSE and the levels of serum copper;there's positive correlation between the scores of MMSE and the levels of serum zinc;while there's no correlation between the scores of MMSE and the levels of serum iron,which suggested the more sever the dementia was,the higher the serum copper was and the lower the serum zinc was. Conclusion There is imbalance of microelements in AD patient whose levels of serum microelements like copper and zinc had some correlation with the severity of dementia.