In recent years, the use of thermoplastic resins rather than thermosetting resins, as part of matrix, in the composite is considered. The use of thermoplastic matrices, due to increased toughness in the composite, is highly regarded. Therm- oplastic matrices compared to thermoset matrices, have advantages such as the ability to recover after manufacturing, rapid manufacturing process, chemical resistance and suitable environment, reducing moisture absorption and reduce costs mainly for high productions. Among thermoplastic composites, glass/polypropylene thermoplastic composite, due to high breakage elongation, special strength and high hardness, suitable bearing pressure, short production time and easily produce unlimited reliability, recovers, light weight and economical, as high performance materials in various industries such as aero space, automotive, shipbuilding and etc are used. Among the various textiles used to reinforce polymer matrix composites, three dimensional braids, are only textiles which due to near net and three dime-nsional structure, lead to interlacing and fibers orientation, continuously and in different directions and develop mechanical properties of three dimensional braid in different directions. Also, three dimensional structure for three dimensional braids, lead to reduction the phenomenon of delamination in this composites. Due to Appropriate proper- ties of glass/polypropylene thermoplastic composites and three dimensional braids, was decided to product glass/poly- propylene three dimensional rectangular braided composite and investigate effect of Structural parameters of three dimensional rectangular braid, including kind of distribution glass fibers in cross-section braid, braiding angle and the number of glass fibers in braid structure, on bending, tensile and impact properties. Also, was produced three dimen- sional rectangular braid by using glass/polypropylene commingled yarn to evaluate effect of commingled yarn on the mechanical properties of braided composite.Results of this work Specified which kind of distribution glass fibers in cross-section braid and braiding angle have a significant effect on tensile strength, elastic modulus, bending strength and bending modulus of braided composite, but not have significant effect on strain tensile and strain bending of braided composite. Also, increase the number of glass fibers in braid structure have a significant effect on bending strength and bending modulus of braided composite. Generally, results showed that increase tensile strength, elastic modulus, bending strength and bending modulus of braided composite by reduction of braiding angle. The increased bending strength and bending modulus of braided composite by increasing the number of glass fibers in braid structure. Using of glass/polypropylene commingled yarn caused a sharp decline in composite porosity and significan- tly increased bending strength of braided composite. Also, results showed that can achieve to good mechanical properties with selection a appropriate braiding angle and without increasing the number glass fibers in braid structure. Keywords: glass/polypropylene Thermoplastic composites, three dimensional braids, bending properties, tensile properties, impact properties.