Aging of sealing ring, shallow sealing groove or improper size of sealing ring will cause oil leakage of automobile slide valve box. Aiming at the problem of oil leakage caused by design defects of the slide valve box, laser scanning was carried on the slide valve box.Through reverse engineering technology, the three-dimensional model of the mold of the conformal sealing ring of the slide valve box was established, then the mold was printed out by stereo lithography 3D printing technology. Finally a mixture of silicone rubber and curing agent was poured into the mold and a sealing ring was obtained by reaction injection.Compared with the traditional injection mold production method, the use of reverse engineering and 3D printing to produce conformal sealing rings can shorten the mold production cycle and reduce mold production cost.Through experimental verification, the oil leakage problem of a automobile slide valve boxis solved effectively.