Luxi ophiolitic mélange zone, situated along the Lushui-Longling-Ruili Fault in the southeastern margin of the Gaoligong Tectonic Belt between the Tengchong and Baoshan terranes in western Yunnan, has been debated on its origin, with models suggesting subduction and accretion from the Meso-Tethys Ocean or rifting induced by continental lithospheric thinning. Identifying the characteristics of mafic magmatic rocks within the mélange zone is crucial to resolving this debate. Through large-scale mapping, we discovered a series of alkaline magmatic rocks including lamprophyres, amphibole-bearing basalts, and TiO2-rich basalts in the Late Triassic to Early Jurassic turbidites. This study employs mineralogical, petrogenetic, and geochemical methods to investigate their genesis and tectonic background. The lamprophyres are classified as sannaites, and have a porphyritic texture and amygdaloidal structure with the phenocrysts of kaersutite, Ti-augite, and Ti-biotite, and matrix of cryptocrystalline potassium feldspar and minor albite. Geochemically, they belong to potassic alkaline lamprophyres, with K2O/Na2O ratios of 1.6 to 3.3 and Mg# values of 50 to 56, and their trace and rare earth element characteristics are similar to those of OIB, but their K, Ba, Sr, Nb, Ta and light rare earth elements are more enriched than those of OIB. Compared to the primitive mantle, the lamprophyres show low Mg# values, depleted Co, Cr, and Ni, with a negative Pb anomaly and without Eu and Ce anomalies, which suggest their magmas underwent the fractional crystallization of olivine and pyroxene, but did not experience the fractional crystallization of plagioclase, and did not suffer crustal contamination and alteration subsequently. The lamprophyres characterized by low εNd(t) (+3.57~+3.73), high 87Sr/86Sri (0.706027~0.706161), high (La/Yb)N (27.8~28) and Dy/Yb (2.6~2.7) suggest they originated from weakly depleted mantle regions, bearing phlogopite and amphibole and within the garnet-bearing lithosphere-asthenosphere boundary. The Ti-rich basalts are alkaline, and resemble the lamprophyres in trace element characteristics and Nd(t) values, but they lack hydrous minerals of amphibole and biotite. The amphibole-bearing basalts lie between the lamprophyres and Ti-rich basalts in mineral assemblage, containing TiO2-rich amphibole and biotite as well as plagioclase phenocrysts. In comparison with the regional mafic magmatic rocks, we conclude that these alkaline mafic magmatic rocks are probably formed during the Jurassic period, and are attributed closely to the asthenospheric convection generated by the Paleo-Tethys Ocean subduction that caused thinning and rifting of the Luxi lithosphere. This study demonstrates that the Luxi ophiolitic mélange is a rifting complex. These findings provide significant constraints for understanding the tectonic evolution of the southeastern Qinghai-Tibet Plateau during the Mesozoic era.