The invention relates to a catalyst prepared through a method for producing trans-decalin with industrial naphthalene being a raw material and the method of the catalyst. The catalyst is a body-type Ni-Mo and/or Ni-W and/or Ni-Mo-W metal reduced catalyst which is partially vulcanized, in a steady-state fixed-bed reactor, on the condition of being 1-10 MPa, 120-280 DEG C and having liquid hourly space velocity of 1-10 h<-1>, trans-decalin is produced through naphthalene hydrogenation. The conversion ratio of naphthalene is nearly 100%, the selectivity of trans-decalin is higher than 90%, and the catalyst is good in long-term cycle operation performance. A test result shows that the process technology is advanced, and the operation is stable and reliable.