Cereal-based complementary food for infants and young children is an important energy source for infants and young children nutrition. The main raw material for the cereal-based complementary food is rice. While, rice can easily absorb heavy metal Cd from the soil and water in growing process, result in a relatively high residual concentration of Cd in rice, and posing a potential threat. In this paper, a new strategy for determination of heavy metal Cd in cereal-based complementary food for infants and young children by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) was proposed. The sample was directly determined by ICP-MS/MS after microwave digestion. The main spectral interferences in the determination process were Mo based polyatomic interference ions (MoO⁺, MoN⁺, MoC⁺) formed by high concentration Mo, and isobar (¹¹²Sn⁺, ¹¹⁴Sn⁺, ¹¹⁶Sn⁺) formed by Sn. In order to eliminate these interferences, in the MS/MS mode, using H₂, NH₃/He, and O₂ as reaction gas, the interference elimination effect and analysis sensitivity of different Cd isotopes were investigated. The results show that in the H₂ and NH₃/He reaction mode, both H₂ and NH₃ can undergo mass shift reaction with Mo-based interfering ions, but cannot react with Sn⁺. ¹¹⁰Cd⁺, ¹¹¹Cd⁺, ¹¹³Cd⁺ can be selected for determination. However, the reaction speed of H₂ and Mo-based interfering ions is slow, and it is difficult to completely eliminate the mass spectral interference of Cd in high-concentration Mo-based matrix. In the O₂ reaction mode, all interfering ions can undergo mass shift reaction with O₂. Although the analytical sensitivity obtained is slightly lower than that in the NH₃/He reaction mode, the background equivalent concentration (BEC) is significantly lower than that in the NH₃/He reaction mode. The optimal analysis scheme for eliminating the interference in the determination of Cd with O₂ as the reaction gas was determined. The accuracy of the method was evaluated by using standard reference materials, and the reliability of the method was verified by comparative analysis with the national standard method (GB5009.268—2016). The results showed that the LOD of Cd is 2.03~13.4 ng·L^-1, and the measured value of the standard reference materials is basically the same as the certified value. At the 95% confidence level, there is no significant difference between the comparative analysis results. The method has high sensitivity, accurate and reliable results, and is suitable for the high-throughput determination of heavy metal Cd in large quantities of cereal-based complementary food for infants and young children.