The invention discloses a leather softening agent which is prepared from the following raw materials in parts by weight: 15-35 parts of polyether-modified hydrophilic silicon oil, 10-22 parts of phosphoglyceride, 8-25 parts of sodium dodecyl sulfonate, 40-60 parts of alcohol, 5-15 parts of peregal, 30-50 parts of water and 0-3 parts of lemon essential oil. Active ingredients in the leather softening agent disclosed by the invention can enter the leather very well to form hydrogen bond binding with hydrophilic groups on fibers inside the leather, so that the interwoven or hardened fibers are separated or re-formed into sequenced arrangement, the elastic force of the leather is recovered by increasing gaps among the fibers, and the good gas permeability of the leather is supplemented; the active ingredients are bridged inside the leather, so that the fibers inside the leather and grease are firmly connected and the grease inside the leather is not prone to volatilize, and the service life of the leather is prolonged. The leather treated by the leather softening agent disclosed by the invention has characteristics of good air permeability, softness, rebound resilience and a smooth hand feeling.