The invention is particularly related with a method, which use bioaugmentation with anaerobic rumen fungi at varied ratios of inoculums on the performance of anaerobic digesters of microalgae biomass for increasing methane production. In that proposed method the composite obtain that 4 isolated species of anaerobic rumen fungi of Orpinomyces sp., Piromyces sp. And Anaeromyces sp., Neocallimastix frontalis were selected and these species were mixed. After that, mixture of rumen fungi containing 4 species was added into the anaerobic digesters fed with microalgae Haematoccus pluvialis at different inoculums ratios: %1 (F1), 5% (F2), 10% (F3), 15% (F4) and 20% (F5) (v/v).