The invention provides a preparation method of a porous implant filled with O-intersecting lines units. The preparation method comprises the following steps: drawing a three-dimensional model of the O-intersecting lines units, controlling the bore diameter, wall thickness and porosity of the three-dimensional model according to the given specific dimension so as to generate a unit structure cell body, carrying out array copying operation on the unit structure cell body, thus obtaining a space porous network body, introducing in a femoral three-dimensional surface model, scaling the model to reach the proportion actually needed, carrying out cutting and Boolean operation on the porous network body and the femoral three-dimensional surface, thus obtaining a porous main body part, drawing the femoral steam end and a bolt positioning hole part by utilizing three-dimensional modeling, combing the porous main body part to enable the porous main body part to form a single-output porous implant body, saving the single-output porous implant body into an output format file and transmitting the file to layering software, adding with a bottom surface support, printing the porous implant body by adopting a 3D printer, clearing a substrate plate, taking out the porous implant, carrying out sand blasting treatment on the porous implant, and packaging the porous implant. With the adoption of the preparation method, units which are regular and uniform and having no closure can be generated, and the stressing uniformity is guaranteed.