The present study, black soldier flies (Hermetia illucens) fermented using lactic acid bacteria were powdered without defatting and added to 3% or 5% to make pig feed. Weaning piglets were fed 3% (T3) or 5% (T5) feed powdered with Hermetia illucens for 5 months and the efficacy of the feed was investigated. The results of measuring body weight gain over 5 months after adding 3% (T3) or 5% (T5) of Hermetia illucens powder to the feed of weaned piglets showed significant weight gain in the T5 group compared to the control group. The added feed to Hermetia illucens powder did not show toxicity, and analysis of its effect on blood properties showed that white blood cell levels tended to increase in the T3 or T5 group compared to the control group.The only increase in white blood cell count was a change within the normal range. As a result of analyzing the effect of the level of addition of Hermetia illucens powder on feces, the effect of liquid reduction showed excellent results in the T3 treatment group and maintained the best form of feces. In this study, the thawing loss in the control group was 6.66%, and the T3 group with added powder to Hermetia illucens showed a significant decrease of 5.03%, and the T5 group also showed a decrease of 5.61%. Therefore, it was demonstrated that additive feed for Hermetia illucens reduced thawing loss, affected the water holding capacity of meat, and played an important role in maintaining the taste of meat. Moreover, the results of carcass grade showed a tendency for one grade to increase in the T3 and T5 groups fed additive feed to Hermetia illucens compared to the control group. In conclusion, the results of this study suggest that feed supplemented with Hermetia illucens is effective in influencing the weight gain of pigs, reducing the liquid content of feces, and increasing carcass grade.