A deodorant for treating sediment in-situ, a deodorizing method and associated facilities. The deodorant is a calcium nitrate solution with a mass percentage of 14.32% to 52.49%. The deodorizing method comprises: (a) determining acid volatile sulfides content and total organic carbon content of sediments to be deodorized, and calculating the dosage of calcium nitrate solution required for deodorization: (b) ploughing the bed of the treatment area by injection tines of a bioremediator and at the same time injecting calcium nitrate solution into the sediment; after the bioremediator has navigated forward, the trench sides of the ploughed furrows will collapse, thus encapsulating the calcium nitrate solution within the sediment. The facilities for deodorizing sediment in-situ are comprise 4 systems, namely an injection system, a storage system, two supply systems and a navigation system.