The invention discloses a tobacco moistening agent and application thereof. After alkali metal salt, sea algae extracts, natural moisturizing factors, amino acid and polyhydric alcohols are evenly mixed under a heating condition, a required tobacco moistening agent is obtained. The tobacco moistening agent can be applied to pipe tobacco, paper-making mode reconstruction tobacco, cigarette paper, a cigarette holder and other tobacco products. Taking the pipe tobacco as a sample, if the weight of 0.5-2% of the pipe tobacco is added, the pipe tobacco has the function of obviously keeping moisture of the pipe tobacco, enables cigarette to keep original style, increases smoke wetness, reduces stimulation, and obviously improves comfort of a throat. Raw materials of products are non-toxic and harmless, sufficient in source, simple in technological process, convenient to manufacture, low in cost, and simple in adding technology, does not change existing cigarette production technology, is beneficial to improving core competitiveness of an enterprise, and brings substantial benefits for the enterprise.