Abstract: OBJECTIVE To investigate the changes of trace elements and nutritional state-related indexes of acute leukemia children complicated with respiratory tract infections so as to provide guidance for control of the respiratory tract infections in the acute leukemia children. METHODS A total of 42 acute leukemia children complicated with respiratory tract infections who were treated from Jan 2014 to Nov 2015 were chosen as the group A, meanwhile, 42 acute leukemia children without respiratory tract infections were set as the group B, and 42 healthy children were assigned as the group C.The serum trace elements, free amino acids, and proteometabolism indexes were compared among the three groups of children, and the test results were observed and compared between the patients with upper respiratory tract infections and the patients with lower respiratory tract infections in the group A. RESULTS The level of serum Fe of the group A was (2.28±0.44)mmol/L, lower than (3.34±0.53)mmol/L of the group B and (4.59±0.64)mmol/L of the group C; the level of serum Zn of the group A was (8.37±1.15)μmol/L, lower than (10.48±1.40)μmol/L of the group B and (12.88±1.56)μmol/L of the group C; the level of serum Se of the group A was (0.81±0.09)mmol/L, lower than (1.02±0.11)mmol/L of the group B and (1.20±0.15)mmol/L of the group C.The level of serum Cu of the group A was (19.84±1.81)μmol/L, higher than (17.70±1.62)μmol/L of the group B and (15.35±1.43)μmol/L of the group C; however, the free amino acids and proteometabolism indexes of the group A were lower than those of the group B or C, while the free amino acids and proteometabolism indexes of the group B were lower than those of the group C.Among the patients in the group A, the test results of the patients with lower respiratory tract infections were lower than those of the patients with upper respiratory tract infections, and there was significant difference (P＜0.05). CONCLUSION The acute leukemia children complicated with respiratory tract infections present with poor state of trace elements and nutritional state-related indexes, and the respiratory tract infections may exacerbate the above abnormal indexes.It is necessary to pay attention to the prevention, control, and treatment of the respiratory tract infections in such group of children.