A ceiling lamp suspending device comprise the following elements. A wire connecting box has two ears arranged at two edges thereof. A retaining sheet is below the wire connection box. A through hole is near a center of the retaining sheet. One edge of the through hole is extended with and communicable to a long hole. A stop elastomer is disposed aside the through hole. A part of the stop elastmoer covering the through hole. A retaining block is installed below the retaining sheet. The retaining block has a threaded section and a shaft extended from the threaded section upwards. An upper end of the shaft is a neck portion and a suspending portion. A via hole is formed on the shaft. The suspending portion passes through the through hole of the retaining sheet; and the neck portion is movable in the long hole.