In this work, two sets of high performance polyimide (PI) fibers fabricated by a more environmentally-friendly and highly efficient “reaction-spinning” method were firstly reported. The relationship between the spinning rate, chemical structure and the imidization degree of the PI precursor fibers were investigated, and the results indicated a moderate low spinning speed and relatively flexible molecular chains are both favorable for the partial imidization reaction in the spinning process. 2D WAXD results demonstrate that the rigid PDA-based PI fibers possess a higher alignment of polymer chains along the fiber axis during the spinning compared to the flexible ODA-based PIs, resulting in enhanced mechanical properties, with the tensile strength of 1.2-2.8 GPa and modulus of 53.6-111.2 GPa, respectively. Meanwhile, ODA sets of PI fibers exhibit a higher loop strength and knot strength than the commercial Aramid and PBO fibers. The process used in this study has a significant potential for realizing industrial level production of high strength and high modulus PI fibers.