The invention discloses a determining method for the width of a pressing rod for a longitudinal joint with staggered and lap-jointed U ribs based on a pressing rod and pulling rod model. The determining method is characterized by comprising the following steps that firstly, the U ribs are lap-jointed in a staggered mode in a joint structure; secondly, the anchoring length of the U ribs is determined; finally, the joint bearing capacity and the width of the pressing rod are determined, specifically, the pressing rod and pulling rod model is corrected and the width of the pressing rod is determined; and the step that the U ribs are lap-jointed in the staggered mode in the joint structure comprises the specific sub-steps that one end of each U rib is embedded into a precast section, the otherend of each U rib is bent to 180 degrees and embedded into a joint section, the U ribs on the left and right sides are staggered by a certain distance, and the staggered lap jointing of the U ribs inthe joint section is used for transmitting the bending moment. The determining method has the advantages that the corrected pressing rod and pulling rod model is provided for the longitudinal joint which adopts high-performance concrete pouring and is provided with the staggered and lap-jointed U ribs, and a theoretical formula for calculating the width of the pressing rod is provided based on experiments and finite element analysis.