Using the 1829 felsic intrusive rock samples, which are discriminated and named by the actual mineral modes with the IUGS proposed QAP classification scheme as the benchmark, the author revised the O’Connor (1965) feldspar ternary (a.k.a., normative An—Ab—Or diagram) for classification of the felsic intrusive rocks. The major revisions include that, (1) the lithological boundary between the “trondhjemite” and the K- rich granitoids (granodiorite and granite) is shifted to the new position with the Or/(An+Ab+Or) = 22%, rather than the 30% ratio in the original diagram; (2) the line separating the “trondhjemite” and the “tonalite” is proposed as a transitional boundary, to indicate the fact that some QAP scheme defined tonalitic rocks contains high content of albite norms; (3) a transitional domain is assigned to emphasize the gradual shift from the “trondhjemite” and the “granodiorite”, and the samples plotted within the domain are suggested as the highly evolved rocks among the TTG suites. The projections of typical TTG suite evolves along the “calc- alkaline” trend in the feldspar ternary plot, but the projections of oceanic plagiogranites follows the “trondhjemitic” trend. These two evolution paths can be explained from the perspective of the phase relations of the haplogranodiorite system.