Abstract: The Hongyanxi tunnel is the first highway tunnel in China, which is rich in oil and gas. In order to solve the safety problem of gas and oil during tunnel excavation, on-site detection and carbon isotope laboratory test of gas samples are conducted regarding the rocks at working face, gas and oil-soluble substances. The research results show that the genetic type of oil and gas of this tunnel is of low maturity and this tunnel is unconventional type with high contents of gas. Safe breakthrough is guaranteed for this tunnel with high risk source by adopting comprehensive measures of gas prevention and control training, emergency rescue drill, safety management process normalization, ventilation system improvement, monitoring and control system establishment and special treatment of major risk sources.