The invention discloses a technology for synthesizing nickel carbonyl under medium pressure in a rotating kettle. The technology comprises the following preparation steps of: (1) preparing water-quenched copper-nickel alloy particles; (2) carrying out a carboxylation reaction; (3) separating; and (4) sterilizing residues in the kettle by using hot nitrogen replacement after the reaction is ended, feeding exhausted gas to an incinerator to be subjected to burning treatment, simultaneously recovering heat, opening a discharge hole and discharging the carbonylated alloy in the kettle after the nitrogen sterilization is finished, and then entering next circulation. According to the technology for synthesizing nickel carbonyl under medium pressure in the rotating kettle, the requirement on pressure is low and the pressure only needs 7.5-8.5MPa, the reaction time is greatly shortened by rotation of the rotating kettle, the yield is high, and the reaction speed can be controlled by means of the rotating speed of the rotating kettle if necessary. The rotating kettle is connected with a fixed airtight device through two groups of spiral flexible tube stacks, and therefore a dynamic and static conversion connection between the rotating kettle and other fixed pipelines is finished.