Abstract: OBJECTIVE To compare the difference in the determination of aluminum in Compound Amino Acid injection by ICP-MS, ICP-AES and HPLC. METHODS Compare the linearity, repeatability, accuracy, quantification limit, detection limit and sample determination results of the three methods by methodological verification and sample determination. RESULTS The linearity range of ICP-MS, ICP-AES and HPLC was 5-200 µg·L^-1, the correlation coefficients were all greater than 0.999; the RSD(n=6) of repeatability were 2.4%, 5.5%, and 7.6%; the recovery rates were 103.2%, 106.0%, and 105.7%; the limits of quantification were 1.2, 4.1, 5.0 µg·L^-1, respectively; the detection limits of ICP-MS and ICP-AES were 0.4, 1.2 µg·L^-1. The contents of aluminum in 43 batches of Compound Amino Acid injection were basically the same. CONCLUSION The three methods can satisfy the determination requirements of aluminum in Compound Amino Acid injection. ICP-MS is simple, fast and accurate; HPLC has lower instrument costs and is easier to promote in the laboratory.