Abstract: In order to alleviate the environmental pollution caused by fossil fuels, the bio-briquette fuels were prepared from high-yielding cotton straw and low-yielding walnut shell using a double-heating press at a temperature of 120 ℃. The calorific value, density, composition, impact resistance strength, hydrophobic properties, and pyrolysis characteristics of the biofuels were analyzed, and the quality was evaluated according to the national agricultural industry standard Classes and Specifications for Densified Biofuel (NY/T 2909-2016). The results showed that the high-pressure hybrid bio-briquettes had lower sulfur and higher density, the structures of cellulose, hemicellulose and lignin were changed significantly, and the intermolecular forces between particles were enhanced. When the mass ratio of cotton straw to walnut shell is 9∶1 and the pressure was 15 t, the lower heating value (LHV) of the bio-briquettes reached 18.76 MJ/kg. When the ratio is 8∶2 and the pressure was 15 t, the bio-briquette had the maximum bulk density (1.222 g/cm³) and energy density (3.76 GJ/m³). The mechanical stabilities and the hydrophobic performance of the bio-briquette fuels were enhanced, the impact resistance reached up to 98%, and the LHV, density, ash and moisture of all samples met the requirements of grade B1 of non-wood bio-briquettes. The results of thermogravimetric and infrared analysis explain that high-temperature compression leads to changes in the molecular structure and intermolecular forces of biomass, thereby altering the heat, density, and immobilization of carbon residues in biomass solid fuels. The cost of bio-fuel products for medium-sized factories with an annual output of 3 600 tons is 273.3 yuan/t. Walnut shell and hybrid of cotton straw and walnut shell (9∶1) can both be used as the preferred solid fuels in the local area from the perspective of raw material composition, price and calorific value.