This study was carried out to investigate the quality characteristics of Cordyceps militaris on Tenebrio molitor-added dairy product and antioxidative activities of lactobacillus-fermented C. militaris. The general components of Cordyceps militaris on Tenebrio molitor are moisture 10.85%, crude protein 18.44%, crude fat 2.07%, crude ash 5.46%. The DPPH radical scavenging activities of different solvents were the highest (74.81 EDA%) with hot water extract sample. The DPPH free radical scavenging activity of Streptococcus thermophiles KCCM 3782 strain was highest at 80.01 EDA%. The DPPH free radical scavenging activity of the fermented product was 91.92 EDA%, which was higher than that of the extract (84.69 EDA%). ABTS free radical scavenging activity and SOD activity were also higher in the fermented products. Therefore, the lactic acid fermentation effect of Cordyceps militaris was confirmed. The acidity of fermented milk was high with increasing amount of extracts. The pH of fermented milk reached 4.60-4.66 after 4 h of fermentation, and the number of lactic acid bacteria was highest (11.70 log CFU/mL) with 1% fermented milk. The moisture content of fermented milk showed no significant difference. In addition, contents of crude protein were not significantly different according to addition amount. Regarding Hunter’s color values, L value decreased as the amount of extract increased, whereas a and b values increased. The contents of free amino acids increased with increasing amount of extract. The DPPH and ABTS free radical scavenging abilities of fermented milk were significantly different by the addition amount of extract increased (p<0.05). In the sensory evaluation, fermented milk containing 1% of extract showed the highest preference.