Abstract: Structural equation and Mei conserved quantity of Mei symmetry for Appell equations in holonomic systems are investigated.Appell equations and differential equations of motion for holonomic mechanic systems are established.The definition and the criterion of Mei symmetry for Appell equations under the infinitesimal transformations of groups are also given.The expressions of the structural equation and Mei conserved quantity of Mei symmetry for Appell equations in holonomic systems expressed by Appell functions are obtained.An example is given to illustrate the application of the results.