The invention discloses a new material called polyacetylene-2, 5-methoxyphenyl and a method for preparing the same. The polyacetylene-2,5-methoxyphenyl has a structural formula as shown in figure 4; the preparation method comprises the following steps that: 1,4-dibromo-2,5-dioxygen methyl benzene and acetenyl tri-n-butylstannyl are utilized as main raw materials, dissolved by tetrahydrofuran, heated to a temperature of between 50 and 80 DEG C, stirred, reacted for 12 to 16 hours, then cooled to a temperature of between 10 DEG C below zero and 25 DEG C below zero, added with LDA(lithium dirsopropylamide), stirred for 15 minutes and positioned in a room temperature environment for temperature rise; after the mixture is kept stand for 24 hours, the mixture is separated by filter paper finally, thereby obtaining a polymer. The reaction is completed through only two steps; and the reaction condition is mild and easy to control. The polyacetylene-2, 5-methoxyphenyl provided by the inventionhas wide application prospect in mass gas-sensing materials.