The synthetic leather base is a composite, with the top and lower layers are nonwovens and the middle is woven fabrics. Firstly, the single rip tearing strength and drawing out resistances of the leather base were tested and tearing failure mechanics were analyzed. Then on the above basis, the single rip tearing strength calculation model of the synthetic leather base was built successfully. From theoretical model, main influencing factors are the weft and warp yarn breaking strength and the density of warp and weft yarns in the woven fabric, and also drawing out resistance of the leather base. Finally, experimental verification was made for the established model, which shows that theoretical values conform to the measured values well.