Abstract: According to the experimentation and the theory,research on gas properties and current rush to interception airmass in the delivery pipeline system are made.The studies indicated that the gas thermal insulation coefficient determining primary properties of the air-mass changes apparently instead of a single constant when hydraulic transition process happens So four appropriate processes are given,namely sub process 1 of compressing,sub-process 2 of inflating,sub-process 3 of inflating,and sub process 4 of compressing.In the sub-process 2 of inflating and sub process 4 of compressing,the gas thermal insulation coeff icient is 1.4~1.6,and is 1.15 in other two processes The value of gas thermal insulation coefficient has definitely influence on the result of the analytic root of current rush to interception air-mass in the delivery pipeline system The more small gas thermal insulation coefficient is,the more great the press of current rush to interception air mass is,and and vice versa.