The invention discloses an LPG boat storage tank steel plate and a production method thereof. The steel plate comprises 0.05-0.12wt% of C, 0.30wt% or less of Si, 0.50-1.30wt% of Mn, 0.015wt% or less of P, 0.008wt% or less of S, 0.020-0.060wt% of Al, 0.15-1.20wt% of Cu, 0.20-1.50wt% of Ni, 0.35-1.00wt% of Cr, 0.20-0.60wt% of Mo, 0.008-0.020wt% of Ti, one or more of 0.0020-0.10wt% of Nb, 0.030-0.060wt% of V and 0.0005-0.0020wt% of B, and the balance Fe and inevitable impurities. The method comprises the steps of molten iron advanced desulphurization, converter top and bottom blowing, vacuum treatment, continuous casting, casting blank heating, rolling and heat treatment, the heating temperature of a casting blank is 1170-1250DEG C, and the heating rate of the casting blank is not less than 8min/cm; the blooming temperature is 1050-1150DEG C, the finishing temperature is 850-940DEG C, and the accumulated reduction rate of last three passes is not less than 16%; and heat treatment adopts online quenching and tempering treatment, or adopts offline quenching and tempering treatment. The steel plate obtained in the invention has the advantages of excellent mechanical properties, good hot and cold processing performance, excellent weldability and low sensitivity of weld cracks.