The invention relates to a valve special for an offshore oil drilling platform, in particular to a clamp connector aluminum alloy two-blade-connected vertical check valve which comprises a lower clamp head hemispherical shell, an upper clamp head hemispherical shell, a cylindrical tube and a variable runner valve core, wherein a lower tube end plane at the lower end of a round hole inlet tube on the lower clamp head hemispherical shell is in sealed contact with an inlet tube end plane on a system inlet tube; a lower tube back conical surface on the back side of the lower tube end plane and an inlet tube conical surface on the back side of the inlet tube end plane are in symmetry; a lower tube back conical surface and the inlet tube conical surface are movably matched with a lower clamp right double-conical surface inside a lower clamp right half slip and a lower clamp left double-conical surface inside a lower clamp left half slip; two groups of lower bolts and screw nuts for assembling and fastening in pair are arranged between the lower clamp right half slip and the lower clamp left half slip; a variable runner in the variable runner valve core is gradually changed into a valve core round hole in an upper spherical surface of the valve core from an annular valve core hole in a lower spherical surface of the valve core. Therefore, one-way circulation is ensured when the variable runner valve core moves vertically relative to the cylindrical tube.