Objective To observe the effect of acetated Ringer's solution or lactated Ringer's solution on intra-operative vital signs and blood gas analysis indexes in children (aged 1-6 years) undergoing tibia pseudoarthrosis orthopaedic operation. Methods Sixty-four children who underwent tibial pseudoarthrosis orthopaedic operation admitted to the Department of Anesthesiology of Hunan Children's Hospital from October 2016 to October 2018 were enrolled and anesthesia was performed by general anesthesia combined with epidural anesthesia, children were randomly divided into a sodium lactated Ringer's solution injection group (LR group) and a acetated Ringer's solution injection group (AR group), and different groups of children were treated with the corresponding crystal solution for intra-operative maintenance. The vital signs and results of blood gas analysis, etc of the two groups were compared at T1 (before the operation), T2 (2 hours after the beginning of operation) and T3 (at the end of operation). Results Finally, 22 patients in LR group and 28 patients in AR group had completed the study. The arterial partial pressure of carbondioxide (PaCO2), blood Na+, K+, Ca2+, glucose, hematocrit (HCT), bicarbonate (HCO3-), total hemoglobin (THb), etc laboratory indicators as well as vital signs of heart rate, systolic blood pressure, diastolic blood pressure, body temperature, etc. showed no statistically significant differences between the two groups at T1 (all P > 0.05). The lactate (Lac) levels at T2 and T3 in AR group were obviously lower than those in LR group (mmol/L: T2 was 1.01±0.21 vs. 1.42±0.47, T3 was 1.38±0.53 vs.2.07±0.48, both P < 0.05) , while pH, base excess (BE) and HCO3- were obviously higher in AR group [pH: T2 was 7.35±0.08 vs. 7.32±0.07, T3 was 7.33±0.06 vs. 7.28±0.03; BE (mmol/L): T2 was 1.02±0.18 vs. 0.67±0.45, T3 was 0.03±0.28 vs. -0.01±0.57; HCO3- (mmol/L): T2 was 21.28±1.20 vs. 20.10±0.17, T3 was 21.09±0.28 vs. 19.96±6.67, all P < 0.05]. Conclusion In the orthopaedic surgery of children's tibia pseudoarthrosis orthopaedic operation, acetated Ringer's solution not only can maintain water, electrolyte, acid-base balance and blood circulatory stabilities but also can reduce the increase of lactate level, which is conducive to maintaining the stability of the internal environment in the organism.