An analytical method for the determination of Ca and Cl elements in food was established with inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). The most abundant isotope 40Ca of Ca is suffering from intense interferences from the 40Ar among the argon plasma gas, and 35Cl is subjected to interference from 16O18OH. To avoid the interference, in the MS/MS mode, collision/reaction cell (CRC) was adopted using H2 as the reaction gas, so that H2 will reach with 40Ar+ instead of 40Ca+, A H2 on-mass method was used to eliminate the interference of 40Ar+ on 40Ca+. As mass shift reaction could take place between 35Cl+ and H2 to generate H235Cl+, thus the interference of 16O18OH+ on 35Cl+ can be eliminated by determining H235Cl+. Ca and Cl showed good linearity in the concentration range of 0.0～100.0 μg·L-1 with linear correlation coefficient (R2)≥0.999 9, and the detection limits of Ca and Cl were 0.061 and 2.32 μg·L-1, respectively. The accuracy and precision of this method were verified by series of national standard materials. The results of this method were basically consistent with the certified values of the reference materials, indicating that the method of good accuracy and high precision. The new method can be used to achieve the accurate determination of Ca and Cl in food.