Mechanical spectroscopy measurement is performed to study the inteal friction of nanocrystalline (NC) nickel with an average grain size of 23 nm from room temperature to 610 K.An inteal friction peak is observed at about 550 K,which corresponds to the Curie transition process of the NC nickel according to the result of magnetization test.Moreover,the fact that the Curie temperature of NC nickel is lower than that of coarse-grained nickel is explained by an analytical model based on the weakening of cohesive energy.