The invention discloses a silk quilt having a lasting warm-keeping effect and a preparation method of the silk quilt, and relates to the technical field of home textiles. The preparation method of the silk quilt having the lasting warm-keeping effect comprises the following steps: boiling cocoons with the addition of a fixing agent which is used for conducting sericin fixation treatment on silk for 30-60min under the following conditions: a temperature is 30-50 DEG C and a pH value is 2-5, and washing the cocoons with water so as to obtain first silk fibers, wherein the fixing agent consists of a fixer and an accelerant, the fixer consists of a compound containing rare-earth metal ions and the accelerant consists of ammonium compounds; mixing the first silk fibers with a refining agent, so as to obtain second silk fibers; and finishing the second silk fibers so as to obtain a first silk layer. The invention also provides the silk quilt having the lasting warm-keeping effect, wherein the silk quilt is prepared by virtue of the preparation method. The preparation method is simple; and the prepared silk quilt is skin-friendly and wear-resistant and has the lasting warm-keeping effect.