Abstract: A preliminary study shows that the Honggong pluton, formally considered as typical I-type granite rock, is proved to be of aluminum A-type. This pluton is characterized by rich potassium, with K2O contents more than 5% and K2O/ Na2O ratios over 1.2. The rocks are metaluminous to slightly peraluminous, with A/NKC values range from 0.80 to 1.14. They also have higher FeO*/MgO ratios, with the mean value of 14.20, which is higher than that of the M- , S- and I-type granites. The granites have higher rare earth element abundances, withΣREE values of 313.09×10-6～523.73×10-6, and have higher Ga/Al（×104）ratios (=2.92～4.29) and (Zr+Nb+Ce+Y) values (551.5×10－6～987.4×10－6), but depleted in Sr, Ba, P, Ti, etc. The Nd isotope model ages vary between 1.3Ga and 1.6 Ga, from which it is deduced that the Honggong granite pluton is on the whole originated from the partial melting of crustal rocks. Integrated geological, geochemical data as well as its feature of tectonic passive location suggest that the Honggang granite pluton was formed under a tensile tectonic setting.