Abstract: Relations between crack arrest toughness K_ca at-10℃ and carborn equivalent carbon equivalent, grain size G_S, phosphorus content w (P) and thickness t of high strength thick plate were analyzed by 26 groups of test data.Results indicate that C_eq, grain size, phosphorus content and crack arrest roughness K_ca at -10℃ are correlative. K_ca at -10℃ increases with the increasing of C_eq and grain size and the decreasing of phosphorus content and thickness. The regression equation of carborn equivalent C_eq, grain size G_S, phosphorus content w (P), thickness and K_ca at -10℃ is proposed based on the results above:K_ca^-10=23 443.45·C_ep+ 276.51·G_S-0.77·w (P) ·t³-2.75·t^1.5.