Thermodynamic property is an inherent attribute of nano materials. How to acquire nanothermodynamic functions is still a great challenge. In this study, grenade-like ZnO micro/nano structures were achieved by a facile microemulsion-mediated hydrothermal route. Through building the relationship between thermodynamic functions of nano ZnO and bulk ZnO, we successfully acquired the standard molar enthalpies of formation, standard molar Gibbs free energies of formation and standard molar entropies of the products by in situ microcalorimetry. Also, the significant influences of surface effect of nanomaterial on thermodynamic functions were discussed. It is an effective strategy for nanothermodynamic functions through building the relationship between nano material, and its corresponding bulk material.