The utility model relates to a medium-pressure steam inlet insertion tube of a steam turbine, in particular to a laminated medium-pressure steam inlet insertion tube of a steam turbine. The utility model aims to solve the problems that the structure form of the conventional medium-pressure steam inlet insertion tube of the steam turbine cannot be used for decreasing the gas leakage loss of the medium-pressure steam inlet insertion tube, so that the steam inlet efficiency of the medium-pressure steam inlet insertion tube and the efficiency of a medium-pressure cylinder are reduced. The laminated medium-pressure steam inlet insertion tube of the steam turbine comprises an insertion tube main body, a plurality of inner sealing rings and a plurality of outer sealing rings, wherein the insertion tube main body comprises an upper tube body and a lower tube body, the upper tube body is integrally fixedly connected with the lower tube body from top to bottom, a plurality of inner sealing rings and a plurality of outer sealing rings are intersected and overlapped in the upper tube body, a first radial gap is formed between each inner sealing ring and the inner sidewall of the upper tube body, and a second radial gap is formed between each outer sealing ring and the outer sidewall of the cylinder. The laminated medium-pressure steam inlet insertion tube of the steam turbine, provided by the utility model, can be used for connecting an inner medium-pressure cylinder of the steam turbine.