The invention discloses sansevieria trifasciata saponin, a preparation method and application thereof. The method comprises the following steps of: making the sansevieria trifasciata into dry powder, extracting by using water, alcohol or methanol, extracting by using petroleum ether or ether, and extracting by using butyl alcohol or pentanol to obtain the sansevieria trifasciata total saponin extract. The method for preparing the sansevieria trifasciata saponi optimizes the process conditions, has simple operation and low cost, has low requirement on process equipment, can reduce the consumption of solvents and enhance the leaching rate. The sterilized sansevieria trifasciata has obvious inhibition function on the growth of JurKet, has no activity killing effect on human cervical carcinoma cells (HeLa) and human gastric carcinoma cells (BGC823), and has no injury to normal Chinese Hamster Ovary (CHO), and the cell grows normally without any obvious change.