The invention provides a steel plate for a seamless high pressure gas cylinder. The steel plate is characterized by comprising the following components, by weight, 0.28- 0.40% of C, 0.20-0.40% of Si, 0.50-1.50% of Mn, 0.010% or less of S, 0.015% or less of P, 1.20% or less of C, 0.50% or less of Mo, 0.10-0.50% of Ni, 0.010-0.030% of Ti, 0.050% or less of Al, and the balance of iron (Fe) and other inevitable impurities. The invention further provides a manufacture method for the steel plate. The method comprises processes of smelting, hot rolling, reeling, holding, quenching and tempering. According to the present invention, after quenched-tempered heat treatment, yielding strength of the steel plate is higher than 990 MPa and tensile strength of the steel plate exceeds 1100 MPa, and impact energy of the steel plate is over 40J/cm<2> at a temperature of -50 DEG C, such that the steel plate can be used for manufacturing various compressed gas steel cylinders, particularly high pressure gas cylinders.