Ages and tectonic implications of the Eraly Cretaceous rhyolites in the west of the Songliao Basin and Da Hinggan Mountains were obtained using zircon UPb dating, petrography analyses and geochemical researche methods. The zircon UPb dating by LAMCICPMS and SHRIMP techniqu, indicate that the crystallizing age of the rhyolites, was from 131.6±06Ma to 123.9±1.7Ma, which belongs to Early Cretaceous. Geochemical researches indicate that the rhyolites from Manduhu area are rich in silica (SiO2＝69.08%~79.58%), alkali (K2O＋Na2O 5.93%~9.76%, average＝8.14), K (K2O/Na2O＞1.0, average＝2.14), poor in calcium (average＝0.60), magnesium (average＝0.27) and have high FeOT/MgO (average＝6.77) ratio, which is a typical highK calcalkaline to shoshonitic series with the character of metaluminous (A/CNK＝1.35~1.78). Early Cretaceous rhyolites are classified as two major types in terms of rare earth element and trace elements geochemistry: I type rhyolites and II type rhyolites. The rocks have high contents of rare earth elements with ∑REE＝149.04×10-6~213.18×10-6(average＝172.35×10-6), enriched in LREE \[(La/Yb)N＝4.89~11.87\], LILEs (Rb, Ba, Th, K) and depleted in HFSE, especially Nb, Ta, Sr, P and Ti. The δEu values vary from 0.54to 0.88 (average＝0.70) and most rocks have moderate negative Eu anomalies. Similar REE distribution pattern imply that the rhyolites come from the same magma source. Compared with I type rhyolites, the II type rhyolites, with strong negative Eu anomalies (δEu＝0.05~0.46, average＝0.27)，have lower ∑REE(average＝142.60×10-6) and depleted in HFSE (Nb, Ta, Sr, P and Ti). The types (I, II) rhyolites with the characteristics of postcollision granites, have lower Sr(＜206×10-6), high Yb(＞2) and well geochemical correlation. Combining with previous studies, we suggest that the rhyolitic magma, which caused by Mongolia Okhotsk postcollisional action, was ogigrinated from partial melting of crustal materials and suffered fractional crystallization, and the rhyolites formed in the interpolateextending settings. The conclusions have most important significance for studying the volcanic action and tectonic settings of Early Cretaceous volcanic rocks.