The invention discloses L485M pipeline steel excellent in low-temperature toughness and a manufacturing method of the pipeline steel. The steel comprises 0.045%-0.065% of C, 0.10%-0.25% of Si, 1.55%-1.65% of Mn, 0.055%-0.075% of Nb, 0.010%-0.025% of Ti, 0.10%-0.15% of Mo, 0.20%-0.30% of Cr, 0.015%-0.045% of Als, smaller than or equal to 0.015% of P, smaller than or equal to 0.003% of S, smaller than or equal to 0.006% of N, and the balance Fe and inevitable impurities, and Pcm is smaller than or equal to 0.18%. The continuous cast blank thickness is smaller than or equal to 170 mm, hot charging is performed at 500-850 DEG C, heating is performed to 1160-1200 DEG C, the rough rolling final rolling temperature is larger than or equal to 980 DEG C, the finish rolling final rolling temperatureis 780-820 DEG C, the finish rolling total downward pressing rate is larger than or equal to 65%, then cooling is firstly performed at the speed of 40-60 DEG C/s till 550-600 DEG C is achieved, and then final cooling is performed at 10-25 DEG C/s till reeling is performed at 400-500 DEG C. A plate coil has excellent low temperature toughness, and using in extremely cold zones and regions harsh incondition is achieved.