The invention discloses a new flucloxacillin sodium crystal form as well as a preparation method and an application thereof, and belongs to the field of medical technologies. An X-ray powder diffraction pattern of the new flucloxacillin sodium crystal form has a strongest diffraction peak namely I/I0=100 when 2theta=11.377 degrees; and an infrared spectrum has characteristic absorption at 792, 896, 1249, 1323, 1400, 1454, 1508, 1600, 1770, 2977 and 3367 cm<-1>. The preparation method comprises the following steps: dissolving flucloxacillin sodium into a ketone solvent, and filtering to obtain a solution A; adding an ether solvent into the solution A, stirring, and cooling to obtain a solution B; and adding an ester solvent into the solution B, stirring for crystallization, filtering, and performing vacuum drying to obtain the new crystal form. The invention also discloses the application of the new crystal form. The new crystal form is easy to dry, can effectively reduce the drying time and reduce the risk of impurity increase, and has a relatively good effect for quality control.