A method for estimating at least one of the characteristics of the biodegradation of a substrate by anaerobic digestion in a methanizer which comprises at least the following steps: a) spectral data in the near infrared of a sample of said substrate from a spectroscopy analysis system are received or spectral data in the near infrared of a sample of said substrate are acquired; b) characteristics of said substrate are predicted from said spectral data in the near infrared of the sample of the substrate, with at least one model for predicting characteristics of a substrate intended to be incorporated into a methanizer in order to be biodegraded by anaerobic digestion, said predicted characteristics of the substrate comprise at least: - the biochemical methane potential of the substrate, abbreviated «BMP of the substrate», - time required for the production of methane expressed in percentage of BMP of the substrate; c) from the predicted characteristics consisting in the BMP of the substrate and in the time required for methane production expressed in percentage of BMP of the substrate, a curve of the cumulative amount of methane produced as a function of time is established, said curve is called «predicted curve»; d) at least one mathematical model of anaerobic digestion is implemented based on at least one of the characteristics of the substrate that have been predicted in step b) except that of the time required for methane production expressed in percentage of BMP of the substrate so as to determine a characteristic of degradation kinetics of said substrate for which a curve of the cumulative amount of methane produced as a function of time having a minimum deviation from the curve called «predicted curve» (established in step c) is obtained from this mathematical model of anaerobic digestion; e) at least one mathematical model of anaerobic digestion is implemented based on the characteristic of degradation kinetics of said substrate determined in step d) and on at least one of the characteristics of the substrate predicted in step b) except that of the time required for methane production expressed in percentage of BMP of the substrate so as to determine an estimation of at least one of the characteristics of the biodegradation of said substrate by anaerobic digestion in a methanizer. a) spectral data in the near infrared of a sample of said substrate from a spectroscopy analysis system are received or spectral data in the near infrared of a sample of said substrate are acquired; b) characteristics of said substrate are predicted from said spectral data in the near infrared of the sample of the substrate, with at least one model for predicting characteristics of a substrate intended to be incorporated into a methanizer in order to be biodegraded by anaerobic digestion, said predicted characteristics of the substrate comprise at least: - the biochemical methane potential of the substrate, abbreviated «BMP of the substrate», - time required for the production of methane expressed in percentage of BMP of the substrate; - the biochemical methane potential of the substrate, abbreviated «BMP of the substrate», - time required for the production of methane expressed in percentage of BMP of the substrate; c) from the predicted characteristics consisting in the BMP of the substrate and in the time required for methane production expressed in percentage of BMP of the substrate, a curve of the cumulative amount of methane produced as a function of time is established, said curve is called «predicted curve»; d) at least one mathematical model of anaerobic digestion is implemented based on at least one of the characteristics of the substrate that have been predicted in step b) except that of the time required for methane production expressed in percentage of BMP of the substrate so as to determine a characteristic of degradation kinetics of said substrate for which a curve of the cumulative amount of methane produced as a function of time having a minimum deviation from the curve called «predicted curve» (established in step c) is obtained from this mathematical model of anaerobic digestion; e) at least one mathematical model of anaerobic digestion is implemented based on the characteristic of degradation kinetics of said substrate determined in step d) and on at least one of the characteristics of the substrate predicted in step b) except that of the time required for methane production expressed in percentage of BMP of the substrate so as to determine an estimation of at least one of the characteristics of the biodegradation of said substrate by anaerobic digestion in a methanizer.