The invention provides a high-solid-content white filling putty and a preparation method thereof. The filling putty comprises the components of, by weight: 20-50% of linseed oil, 1.0-2.5% of organic bentonite, 20-35% of heavy calcium, 10-20% of barium sulfate, and 10-30% of rutile titanium dioxide. The high-solid-content white filling putty provided by the invention is a functional product with an excellent environment-protection performance. No arene, ether or ether ester is added in the putty, such that the putty causes no damage to the health of the operator. The putty is not categorized as a hazardous chemical, and is safe and reliable in production, transportation, and application. The putty provided by the invention can be applied in a scraping smear process. The putty is characterized by low smell, high solid content, high filling property, and the like. The putty satisfies the requirements of HG/T3356-2003 on various nitrocellulose putty products.