Objective To find a proper way for accurate results on complete blood counts.Methods Based on the results from automatic hematology analyzer, set up criteria for blood cell microscopic examination. 9 992 blood specimens were detected and the results were analyzed according to the criteria, statistics on the data were made to find out the reliability of the policy.Results The criteria could help to find more abnormal cells, it was very useful for clinical diagnosis and proper treatment.There were 29.3% of CBC specimens needed for microscopic examination, 32.2% of which had increased bands or increased atypical lymphocytes or other abnormalities.Conclusions It was very important to set up the criteria for performing peripheral blood smear. It can provide more accurate and reliable information to clinical doctors.