The Yulong giant porphyry Cu deposit is located in the eastern margin of the Tibet Plateau. It is a typical representative of collisional porphyry copper deposits. Recent studies indicate disparities in the mineralization potential between the ore-forming and ore-bearing porphyries of the Yulong deposit. Here we present whole-rock main/trace elements, whole-rock Sr-Nd, zircon U-Pb, and zircon trace elements data for ore-bearing monzogranite porphyry and ore-forming granite porphyry of the Yulong deposit to delve into the magmagenesis of this deposit and the intrinsic factors influencing its mineralization potential. Zircon U-Pb dating shows that the Yulong porphyry were emplaced at ca. 42~41 Ma. Monzogranite porphyry and granite porphyry have similar Sr-Nd ratio, including high (⁸⁷Sr/⁸⁶Sr)_i (0.706 0~0.707 6 and 0.706 2~0.706 7) with low εNd(t) (-2.9~-2.0 and -4.6~-1.9). High K₂O (the average＞4%), low MgO, Mg^# and Cr, significant negative Nb and Tb anomalies, low Nb/U and Ce/Pb ratios were derived from partial melting of a thickened lower crust. Combine with adakitic signatures of monzogranite, including high SiO₂, Al₂O₃ and Sr contents, low Y and Yb contents with high Sr/Y and La/Yb ratios, we propose that the Yulong metallogenic mother magma originated from the partial melting of the Cenozoic lower crust. Zircon trace-element analysis shows that the two porphyries of Yulong have high Eu/Eu^*(>0.44), 10 000×(Eu/Eu^*)/Y(>3.6), (Ce/Nd)/Y(>0.01) and lower Dy/Yb (<0.31, average 0.22), suggesting that both porphyries have high and similar magma water content. Moreover, trace elements in zircons shows that monzogranite porphyry ΔFMQ= 0.29~2.29 (average 1.44), and granite porphyry ΔFMQ=1.07~2.74(average 1.80). They both have high magmatic oxygen fugacity, but the granite porphyry has a larger range of variation. In addition, the oxygen fugacity is higher than that of monzogranite, suggesting that different oxygen fugacity may affect the differences in mineralization.