Six new squalene derived polyether glycosides, onygenaleosides A-F ( 1 - 6 ), that possess a 6/5 bicyclic fused ring skeleton were isolated from the cultures of Onygenales sp. YX1425, along with two known analogues ( 7 and 8 ). The planar structures of the new compounds were elucidated based on analysis of NMR and MS spectroscopy data, and the absolute configuration of 1 was determined by the advanced Mosher method and quantum chemical calculations. Compound 2 was active against Spodoptera frugiperda with an LC 50 value of 193.4 ± 1.1 μg/mL.