The invention discloses a method of judging secondary gas explosion in mine thermodynamic disaster relief; the method comprises the steps of I, determining a secondary gas explosion position; II, estimating time for secondary gas explosion to occur in the monitored area, to be specific, 201, acquiring environmental parameters of the monitored area, 202, judging whether the monitored area is an area experiencing high-concentration gas explosion or not, 203, estimating time and probability for the high-concentration gas explosion to occur and 204, estimating time and probability for low-concentration gas explosion; III, estimating time for the secondary gas explosion to occur in the monitored area; IV, displaying and storing in real time, judgment results for the secondary gas explosion. The method of the invention is novel in design, can judge the three key indexes, time, probability and position, of secondary gas explosion in a coal mine, and can provide theoretical reference and guidance for commanding and decision-making for thermodynamic disaster relief.