In the study, the combustion and fuel properties of slurry fuels, which are formed by mixing biomass as agricultural waste, sludge swage and algae, and coal as lignite and anthracite in certain proportions, were investigated. The energy properties of new slurry fuels were compared with fossil fuels such as lignite and anthracite, according to the Van Krevelen diagram used. The required stoichiometric air-fuel ratio (SAFR) amount in the burner was calculated during the combustion process. The real fuel-air ratio (RFAR) amount in the burner was determined during the combustion process according to the excess air coefficient (λ) value of 1.5.; as agricultural waste Rice Husks (RH), Corn Cobs (CS), Walnut Shells (WS), Sunflower Shells (SS), Olive Cake (OC), Woodchips (WC) and as other biomass; Brown algae, sewage sludge have been used. As lignite, eight different types with low fuel properties and anthracite, which is the best coal fuel, were used. In the study, the H/C ratio was found to be 1.126 for the mixture of Anthracite + Sewage Sludge + Sunflower Shells (SS) depending on the sewage sludge for the slurry fuels mixture. If it is dependent on Algae, a value of 1.243 was calculated for the mixture of Muğla Ikizköy + Algae + Sunflower Shells (SS). The O/C ratio was found to be 0.242 for Anthracite + Sewage Sludge + Olive Cake (OC) depending on the sewage sludge for the slurry fuels mixture. For Algae, a value of 0.129 was calculated for the mixture of Anthracite + Algae + Olive Cake (OC).