In order to improve the processing performance of black rice, black rice flour was used as raw material and different amounts of black fungus powder (5.0%, 10.0%, 15.0%, 20%) were added to investigate its effect on the gelatinization and thermodynamic properties of black rice flour. The influence of rheological properties, textural properties and microstructure on its corresponding black rice gel was also studied. Adding Auricularia auricular-judae powder can significantly improve the viscosity of black rice and promote the gelation of black rice during cooling, among which adding 20% Auricularia auricular-judae powder had the best effect. The addition of Auricularia auricular-judae powder can inhibit the flow of water in black rice gel, and increase the hardness and elasticity of black rice gel significantly. The gelatinization enthalpy of black rice gel increased from 3.01 J/g to 5.94 J/g, and the hydroxyl stretching vibration peak of black rice gel decreased from 3 390 cm–1 to 3 374 cm–1. The stability of black rice gel structure was improved by adding Auricularia auricular-judae powder. The SEM results showed that the pores of black rice gel supplemented with Auricularia auricular-judae powder were significantly smaller than that of pure black rice gel, and the matrix layer around the pores was thicker, which further explained the mechanism of Auricularia auricular-judae powder on improving the structure of black rice gel. In conclusion, the effect of Auricularia auricular-judae powder on the physicochemical properties and structure of black rice gel was significant.