In this study the composite reinforcement by a knitting fabric made of glass and polypropylene yarn,a new manufacturing method of composite, and the best type of knit were investigated. In this case various knitting fabric by different percentage of glass and polypropylene(G8%-92%PP,G10%-90%PP,G18%-82%PP,G33%-67%PP,G44%-56%PP) in three types of knit which are called 1*1 Rib, Full Millano and Full Cardigan were produced. The mechanical properties of fabrics in wale, course and diagonal direction were measured. After recognizing the best composite state and preparing the samples in such state the selective mechanical properties of knitting composite were investigated. To predict the mechanical properties of knitting composite, a simulating model was introduced as well. The results show that the 1*1 Rib with 8% glass and 92% polypropylene has the best strength , bending rigidity and hardness, as well as the 1*1 Rib with 18% glass and 82% polypropylene has the best impact property.Finally the results show that all composites have the best properties in their wale direction.