Abstract: As one of the geological disasters in tunnel construction, gas bursts in non-coal measure strata are characterized by randomness and uneven distribution when compared to those that occur in coal strata, making these kinds of gas tunnels more dangerous. Based on the practical case of the Zhegushan tunnel, this paper describes the causes and bursting mechanism of the gas in non-coal strata tunnels in detail based on the analysis of geological conditions, gas level determinations and pressure testing, and gives a prediction criterion for the risk of gas bursts, which can play a guiding role for the research, design and construction of tunnels in non-coal measure strata.