The microstructure characteristics, fracture morphology, tensile properties, impact toughness at low temperature, and strain aging behavior of X90 high-strength pipeline steel were investigated by OM, SEM, TEM, tensile test and Charpy impact test. The results show that X90 high-strength pipeline steel is rather sensitive to strain aging with a sensitive temperature of 423.15 K. After aging treatment above 423.15 K, the X90 pipeline steel loses continuous yielding and strengthening characteristics, and the tensile curve changes from the round-house-type before aging to the Lüders-type yield curve. When the aging time was fixed as t_ag=5 min, with the increasing aging temperature T_ag , the yield strength R_p0.2, tensile strength R_m and yield ratio R_p0.2/R_m of X90 steel all show an increasing trend, and the uniform elongation UEL, fracture strain ε_f, total energy absorbed by low-temperature impact A_k, crack formation energy A_i and crack growth energy A_p all show a decreasing trend. The microstructure of X90 steel before and after aging treatment presents more or less the same complex structure composed of fine acicular ferrite + polygonal ferrite + lath bainite + M-A constituents. Pre-straining and aging treatment are the main inducements of the strain aging behavior of pipes. In the pipe production process, the flexible leveling method could be used to replace the rigid roll leveling method, and the multi-step progressive molding method could be used to replace the one-step spiral molding method to effectively control the pre-strain. It is noted that the temperature of the present coating process should be lowered than 423.15 K to avoid any harmful heat effect on the performance of pipes. Otherwise, one should adopt other coating process, of which the applying temperature should meet the above requirement.