The embodiment of the invention provides a method and system for acquiring least test bill. The method comprises the following steps: acquiring detailed list data of all users and feature factor datacorresponding to a to-be-tested system; if judging that the feature factor data only comprises the first factor data, acquiring a first scene matrix by using approximate matrix multiplication, and acquiring a corresponding user identifier from the detailed list data to form a first scene user matrix; generating the minimum test user set according to the first scene user matrix; acquiring corresponding detailed list data from the detailed list data according to the minimum test user set so as to be served as the least test bill data. The system is used for executing the method. The first scenematrix is acquired by using the approximate matrix multiplication according to the first factor data through the method disclosed by the embodiment of the invention, the first scene user matrix and the least test user set are generated by suing the detailed list data, and the coverage feature factor data comprehensiveness and accuracy are improved when the acquisition amount of the least test userset is reduced.