The effects of microwave nanothawing(MNPT) and microwave thawing (MT) on water holding capacity (WHC)， protein structure， protein and fat oxidation of jumbo squid(Dosidicus gigas) were studied by constructing hydroxyl radical oxidation system. The results indicated that compared with MT， MNPT could reduce the cooking loss and centrifugation loss of jumbo squid， and enhance the WHC. The content of carbonyl group， dityrosine content， turbidity and TBARS value of MT and MNPT groups all increased with the increase of H2O₂ concentration. There were significant differences among different oxidation concentrations (P<0.05)， and all MNPT treatment groups were lower than MT treatment groups with the same concentration of H2O₂. MNPT could effectively alleviate protein and fat oxidation and reduce protein aggregation. Endogenous fluorescence and ultraviolet absorption indicated that MNPT could effectively maintain the stability of protein structure. MNPT is an effective thawing method， which can achieve rapid and uniform thawing.