The objectives of this study were to evaluate biogas production and changes of CH4 contents by trace elements solution dosing to improve the operation efficiency of anaerobic digestion. The solution with trace elements was manufactured by Co, Mo, Ni, and Fe, and the trace elements dosages were gradually increased from reactor R1 to R4. Operation was performed as four modes and organic loading rate was increased from R1 to R4. As a result, digestion efficiency of R2 or R3 was higher than R1 without trace elements solution. Also, it showed that biogas production and CH4 contents of R3 were high compared with R2. However, R4 had a negative effect on the efficiency of anaerobic digestion due to the additional dosing of unnecessary trace elements. Moreover, from the results compared with anaerobic digestion conditions on effect of each trace element, it showed that experiment with the mixture of Co, Ni, Mo, and Fe was the highest digestion efficiency and individual trace element showed high digestion efficiency in the order of Fe, Co, Mo, and Ni. In conclusion, the additional dosing of optimum trace elements is essential to enhance the efficiency of anaerobic digestion.