The invention relates to a preparation method of knitted nonwoven joint cloth, and belongs to the technical field of textiles. The preparation method is carried out on a nonwoven needling machine, andincludes the two steps of needling strengthening and knitted stitch forming; on one hand, a yarn guide device and a yarn threading device are added, on the other hand, first-row needles on a needle plate in the moving direction of a fiber web is changed into latch needles. When felting needles and the latch needles on the needle plate move together, the felting needles can complete nonwoven forming, the latch needles hook and take yarn which is guided out by the yarn guide device into the yarn threading device, and stitch knitting can be completed. Movements of the felting needles and the latch needles are combined together to omit an additional knitted stitch forming device, so that nonwoven forming and knitted forming are combined together to be completed, the time is reduced, the process is simplified, and finally, not only can the knitted nonwoven effect be formed, but also the strength of the joint cloth can be improved. The preparation method is ingenious in design, convenient to operate, unique in product effect and suitable for application and promotion.