The utility model discloses an ocean well drilling marine riser's fixed clamp of auxiliary line, including four split type clamps, external realizing is responsible for at marine riser to these four split type clamps surrounding with the axle center circular arc of end to end component in proper order, and the terminal surface is provided with corresponding auxiliary line half slot respectively outside the both sides of these four split type clamps, and the make -up is realized to the half slot of two adjacent clamps, every clamp comprises upper and lower two backup pads, has welded a connecting plate respectively in both sides butt joint position between two backup pads about every clamp, and two connecting plates have been welded altogether to two butt joint positions of every clamp, andthe connecting plate of adjacent clamp butt joint department is opened has the bolt hole of adjusting well. The utility model discloses a device, need not carry on wire -electrode cutting and circular arc the region round as a ball technology, greatly reduced manufacturing cost, the quality is guaranteed more easily, simple structure, compactness, overall dimension is little, light in weight, easy dismounting.