The invention relates to steel for a 690MPa grade hot rolled thick low-yield-ratio automobile spoke. The steel comprises chemical compositions of, by weight, 0.06-0.10% of C, less than or equal to 0.20% of Si, 1.50-1.70% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.02-0.05% of Al, 0.15-0.25% of Cr, 0.02-0.04% of Nb, 0.01-0.03% of Ti, and the balance Fe and inevitable impurities. The invention further relates to a preparation method for the steel for the 690MPa grade hot rolled thick low-yield-ratio automobile spoke. The preparation method includes the steps ofmolten iron KR desulfurization, LF refining, RH refining, Ca treatment, continuous casting, and a hot rolling process. The preparation method adopts reasonable design of performance, specifications,compositions and the hot rolling process to produce the steel for the 690MPa grade hot rolled thick low-yield-ratio automobile spoke, the steel has high strength, low yield ratio, long fatigue life, high surface quality and stable performance, and meets the requirements of production and users.