The B3LYP theory and scaled hypersphere search method are utilized to explore pathways of (HO) 2PS 2Cu-mediated CH 3OOH decomposition, a model reaction of alkyl hydroperoxide with cuprous dialkyldithiophosphate [(RO) 2PS 2Cu]. It is found that the decomposition of CH 3OOH mediated by the copper(I) complex may lead to formaldehyde and water molecules via O–O bond heterolysis and subsequent intramolecular hydrogen transfer, with retainment of the copper(I) complex. The subsequent hydrogen transfer event and formation of water may add new understanding to the (RO) 2PS 2Cu-mediated decomposition process of alkyl hydroperoxide. The oxygen transfer from CH 3OOH to (HO) 2PS 2Cu moiety, as an O–O bond cleavage manner of CH 3OOH, is also found to occur.