It is the first time that ultrapotassic alkaline rocks are found in Bashikao gong of the Altun Mountain. They occur as enclaves or blocks embedded in pl agioclase amphiolites. The compositions of the ultrapotassic alkaline rocks are: SiO2 40.77%～40.98%, K2O + Na2O = 3.68%～6.94%, K2O >Na2O, K2O/ Na2O = 3. 28～7.76. They belong to the ultrapotassic strongalkaline rocks. Their total R EE contents rang e from 705.68×10-6 to 972.34×10-6. The chondritenormalized REE p atterns show a strong LREE enrichment ((La/Yb)n = 37.27～43.53), and moderate Eu anomalies (Eu=0 .67～0.75). The REE patterns of the rocks are very close to typical ultrapotassi c alkaline rocks. The discovery of ultrapotassic alkaline rocks in this area is of farre aching significance in the research on deep geological processes and tectonic e volution of the study area.