A novel tandem reaction system formed with H2O2 production and in situ fabric bleaching reaction was firstly designed and constructed with Au/TiO2 photocatalyst. Results showed H2O2 generated in situ achieved high-efficiency fabric bleaching under the sunlight excitation, thus successfully constructing a ready-to-use system.·OH was confirmed as the main active specie in the simultaneous fabric bleaching reaction. Herein, to ensure the sufficient H2O2 production is a key factor. The different intensity of strong metal-support interaction (SMSI) was introduced into Au/TiO2 by regulating the calcination atmosphere to boost the H2O2 yield. H2/Ar calcination atmosphere imparted Au/TiO2 the SMSI effect to make H2O2 yield exceed that of counterpart under air atmosphere after 6 h of continuous reaction. The controllable capsulating overlayer on Au NPs provided relatively fewer exposed Au active sites to balance the H2O2 generation and decomposition rates, thus giving a better final yield. This work not only offer a novel path to improve H2O2 generation performance,but also propose new ideas for realizing in situ bleaching using sunlight as driving force and cleaning production of textile printing and dyeing industry.