Abstract: The structure of floors and roof of Harbin Zhongyang Tower is concrete beams and plates prestressed with?unbonded tendons.Compound type houses are on 21st floor and 22nd floor originally.Building owner requires that the?compound type houses be adjusted to 22nd floor and 23rd floor.To complete the task of adjusting house, remodeling of?sealing in local area on top of 21st floor and remodeling of opening in partly floor on top of 22nd floor need to be done.It is?given that the method of sealing remodeling of local floor.It is also presented that design and construction method of post-building beam under plate, design and construction ways of reinforcing beams interrelated posted- building beam and opening?slab, temporary anchor and permanent anchor of prestressing tendons in opening, and reinforcing thought and method of?negative moment region of the plate neighboring holes.It may be served as reference for remodeling design of sealing and?opening of other floor prestressed with unbonded tendons.