The present invention discloses process of assembling dead weight sealed members inside a synthetic tower. The process includes hoisting and assembling the catalyst frame casing, the middle catalyst frame, the middle heat exchanger, the upper catalyst frame and the upper heat exchanger successively into the housing of the synthetic tower. The process features that before each of the catalyst frames is set on corresponding connecting ring and assembled into the catalyst frame casing, the lower end surface is machined into sealed surface fitting the connecting ring. The synthetic tower assembled in the modified process has no driftage and leakage of medium, and raised synthetic ammonia output.