In-situ polymerized anisotropic spinning solution of poly(DACYB/TPC) was prepared by low temperature solution polymerization of DACYB and TPC in N-methyl pyrrolidone with addition of equimolar amount of $Li_2CO_3$, which was directly dry-jet wet spun to give high strength (higher than 20 g/d) and high modulus (higher than 720 g/d) aromatic polyamide fiber. Mechanical properties of the fiber was strongly dependent on the dry-jet wet spinning conditions, i.e., spinneret diameter, spin draw ratio, air gap and heat treatment conditions (temperature and tension). Poly(DACYB/TPC) fiber spun through spinning holes with diameter 0.06 mm had higher tensile property than the fiber spun with diameter 0.15 mm at the same spin draw ratio, The latter, however, had higher tensile property than the former at the identical fiber thickness. Fibers prepared by dry-jet wet spinning through the air gap of around 40 mm gave the best properties by enhancing spin draw ratio. Heat treatment (above 25$0^{circ}C$) under tension (higher than 2 g/d) improved the tensile property of poly(DACYB/TPC) fiber, particularly in tensile modulus.