Objective To discuss the influence of blood exchange transfusions on hemato- microenvironment of neonates with hyperbilirubinemian.Methods Blood exchange transfusion was performed in 35 neonates.Mean transfusion volume was (136.9±27.4) ml/kg.The speed of blood exchange transfusion was 92 ml/(kg·h).Blood bilirubin,blood electrolyte,blood routine and blood sugar levels were measured before,during and after the transfusion.Results Serum total bilirubin (TB) decreased by 53.78% after blood exchange,but there was no change in Na~+,Cl~-,and blood sugar (P＞0.05),and K~+ was remarkably decreased from (4.45±2.40)mmol/L to (3.87±0.52)mmol/L (t=21.979,P＜0.05).TB,Hb,PLT,WBC,Ca~(2+) were decreased[TB from(511.52±80.21) μmol/L to (236.41±66.54) μmol/L;Hb from (145.20±11.70) g/L to (128.66±2.54) g/L;PLT from (207.84±70.67)×10~9/L to (134.86±48.61)×10~9/L;WBC from (16.90±10.56)×10~9/L to (8.94±7.44)×10~9/L,and Ca~(2+) from (1.26±0.32) mmol/L to (0.99±0.22) mmol/L,P＜0.05 or ＜0.01].Conclusions Blood exchange transfusion can not influence Na~+,Cl~-,and blood sugar,but has remarkable effect on total bilirubin,Ca~(2+),Hb,K~+,PLT,and WBC.