Abstract: To expand the application domain of tea tree oil and develop a new natural fresh-keeping agent, the emulsified tea tree oil (ETTO) was prepared with the emulsifier “Span80+Tween80”. Through the detection and analysis of the indexes of illness state, soluble solids content, firmness, respiratory intensity, etc, the application effect of ETTO in the fresh-keeping of bananas under natural condition was discussed, which was further compared with that of commonly-used compound pesticide (composed of agricultural streptomycin, thiophanate-methyl and other pesticides) for banana fresh-keeping. The results showed that ETTO of various concentrations had banana fresh-keeping effects of different levels and better effects with its higher concentration, however, when the concentration of ETTO was beyond 1000 mg/L, the fresh-keeping effect did not remarkably rise with the increase of its concentration. ETTO of 1000 mg/L could remarkably extend the shelf life of bananas. In addition, its effects in inhibiting the conversion of reducing sugar and increase of total soluble solid content of bananas after picking were a little weaker than that of compound pesticide. Its effect in delaying the decrease of banana firmness was equivalent to that of compound pesticide, and its effect in inhibiting banana respiration was obviously better than that of compound pesticide.