In the work, an extension of the eddy-dissipation model (EDM) is developed to simulate turbulent combustion of hydrogen in undiluted oxygen in rocket combustion chambers. The modification of the eddy-dissipation model allows eliminating of main demerits of the original EDM model. This is achieved by introducing additional parameters into the model, which limit the reaction rate and depend on the local stoichiometry and temperature. The main such parameter is "Maximum flame temperature," which depends on local stoichiometry and takes into account the dissociation of combustion products. The extension of the EDM model is based on the framework provided by ANSYS CFX. The new turbulent combustion model is validated against experimental data from three different subscale rocket combustors. The validation of the model is carried out against data on pressure and wall heat flux, which are the main targets of simulations of rocket combustion chambers.