The objective of this study was to investigate effects of diet supplemented with organic trace mineralszinc (Zn) and manganese (Mn) on eggshell quality and blood biochemical indexes of laying hens in middle-late Laying period.A total of 600 Hy-line brownlaying hens aged 65 weeks were randomly divided into 5 groups with 6 replicates per group and 20 hens per replicate.These groups were control group (basal dietsupplemented with inorganic Zn 6.00 mg/kg and inorganic Mn 3.00 mg/kg) and four experimental groups (groups 1 to 4 were basal diet supplementedwithorganic Zn 6.00, 11.00, 16.00 and 21.00 mg/kg, and organic Mn 3.00, 8.00, 13.00 and 18.00 mg/kg, respectively).After feeding for 4 weeks, the eggshell quality and blood biochemical indexes were detected.The results showed as follows: 1) the supplementation of organic Zn and Mn significantly increased eggshell strength compared with the control group (P<0.05),and the effects of groups 2 and 4 were better.2) The egg broken rate was significantly lowerin group 2 than control group (P<0.05), and eggshell thickness was significantly higher than control group (P<0.05).3) Carbonic anhydrase activity and calcium content of serumin groups 2 and 4 weresignificantly higher than the other groups (P<0.05),and the serum phosphoruscontent was highest in group 4.4) Crystalmicrostructure of eggshell was improved, and cracks of eggshell surface were reduced by diets supplemented organic Zn and Mn, and group 2 showed the best effect.In conclusion, diets supplemented with organic Zn and Mn have certain improvement to eggshell quality of laying hens in the middle-late laying period and the addition of 11.00 mg/kg organic Zn and 8.00 mg/kg organic Mn in diet show a better effect in the present study.