The invention provides a base membrane of a medical dental towel and a preparation method thereof. The base membrane of the medical dental towel comprises the following components in percentage by mass: 40-50% of PE particles 7042, 15-25% of PE particles 1C7A, 6-14% of PE particles 2020H, 15-25% of PE particles 8008, 4-7% of an additive 265 and 2-5% of an additive 78CB. The preparation method of the base membrane of the medical dental towel comprises the following steps: A) purchasing the raw materials; B) inspecting prior to stocking; C) getting ingredients; D) stirring and mixing; E) preparing the membrane and forming the same; F) slitting and rolling; G) inspecting and packaging; and H) putting in storage and removing from storage. The process difficulty is reduced when the base membrane and toilet paper are compounded, no glue needs to be used, and released layers are avoided in follow-up use, so that the quality of the finished product is improved.