The invention discloses a finishing process of blue-black double-elasticity denim fabric. The vehicle speed is 55-58m/min, rubber blanket vapor pressure is 29.4N-39.2N, wool blanket vapor pressure is 49N-58.5N, preshrunk ratio is 14%-15%, residual shrinkage ratio is 2%-3%, forming temperature is 180 DEG C-190 DEG C, time is 25s-35s, and forming breadth is 2cm-3cm larger than end product breadth. The finishing process of the blue-black double-elasticity denim fabric is obtained by optimization of a finishing process. The weaving efficiency of the developed blue-black double-elasticity denim fabric reaches more than 86%, and top quality good ratio can reach more than 97%. The developed blue-black double-elasticity denim fabric is distinct in lines, can achieve moisture absorption and breathability, has resilience, is comfortable to wear, and has good economic and social benefits.