The volcanic suite of Guanfang area occurs in the north of South Lancangjiang magmatic tectonic zone within the Sanjiang Three-River tectonic belt. A volcanic suite composed of acidic volcanics of Manghuai Formation and basic volcanics of Xiaodingxi Formation was extruded in the Guanfang area in the middle-Late Triassic period. With high silica（SiO2=75.49% on average），rich potassium（K2O=3.88% on average）,low titanium（TiO2=0.136% on average）and A/CNK high than 1.1（1.53 on average）, the acidic volcanic rocks of Manghuai Formation belong to potassium-rich calc-alkali rhyolitic volcanic rock series. The rocks have an average ∑REE of 276.85×10-6 and show evident nagative Ti, P and Eu anomalies as well as positive K, Rb, Ba, Th anomalies in the trace element spider diagrams.Basic volcanic rocks of Xiaodingxi Formation are also enriched in potassium（K2O=2.68% on average），with their Rittmann index varies in the range of 65.92%～75.68%（σ=6.27 on average）, thus belonging to potassium_high calc-alkalibasalt-shoshonite series. The REE distribution pattern is slightly right oblique with an average ∑REE of 171.83×10-6，and there exist no or very weak nagative Eu anomaliesThe rocks show evident K, Rb, Ba, Th positive anomalies and Ti, Y, Yb, Cr nagative anomalies in the trace element distribution pattern. According to the rock assemblage as well as geological and geochemical haracteristics, it is suggested that the Triassic volcanic suite in Guanfang area along South Lancangjiang belt of Yunnan Province should be composed of epicontinental arc-volcanic rocks. 