Biogas production from lignocellulosic compounds is affected by several parameters. In the present article, Taguchi method was applied in evaluating the parameters including inoculums type (cow rumen and cow dung), pretreatment time (0, 24, 48 h), and total solid content (2, 5, 10 %). The L₁₈ (2¹×3²) full factorial design with a mixed orthogonal array was selected to conduct the experiments. Furthermore, to find the percentage contribution of each parameter on biogas yield, the analysis of variance was applied. The analysis results showed that the best inoculum type was cow rumen (signal-to-noise 27.59), the best pretreatment time was 48 h (signal-to-noise 28.20) and the best total solid was 2% (signal-to-noise 31.98). Furthermore, the percentage contribution of inoculum type, pretreatment time, and total solid was 0.43, 7.97 and 83.51% respectively. It means the total solid was the most effective parameter and then it was followed by pretreatment and inoculums. The predicted maximum biogas yield of 42.59 L/kg resulted from an optimum condition of inoculum of cow rumen, pretreatment time of 48 h, and a total solid of 2%. In the confirmation test, the Taguchi method could predict biogas yield successfully with R² of 0.919.