The catalytic dehydro-aromatization reaction over Mo/HZSM-5 catalyst was drastically stabilized by the co-addition of 5.4% H2 and 1.8% H2O to methane feed at 750 °C, 0.3 MPa and methane space velocity of 3000 mL g−1 h−1, suppressing the coke formation effectively, compared with single hydrogen or steam addition.