The invention discloses a super-thick plate accelerated-cooling method based on inclined jet flow. According to the method, three-section type accelerated cooling for a jet flow cooling area is achieved by adopting forward jetting and reverse jetting as independent units and combined units, or adopting forward jetting, forward jetting and reverse jetting as independent units and combined units, and accelerated cooling for super-thick plates is achieved through cooling speed control of different temperature sections, surface cooling temperature control, heat return time control and matched setting of corresponding water cooling parameters. Through integrated control over different temperature sections, the cooling speed and phase change structures of the super-thick plates, cooling paths and super-thick plate cooling are organically combined, the temperature gradient in the thickness direction of the super-thick plates is greatly reduced, and a process window is provided for development of new steel types for super-thick plates with diversified performance requirements.