In　order　to　investigate　a　mechanism　of　infrasonic　signals,　we　have　developed　a　device,　which　can　collect　infrasonic　sound　wave　automatically.　The　system　can　not　only　record　graphs　but　also　store　data　files.　Programmed　by　corresponding　software,　the　recorded　infrasonic　signals　can　be　analyzed　and　dealt　with;　therefore　this　system　has　altered　the　status　which　can　only　record　single　graphics.　The　paper　has　introduced　the　working　elements,　software　and　hardware　scheme　of　the　infrasonic　observation　system.　Some　abnormal　infrasonic　signals　observed　by　this　system　are　offered　provided,　and　the　methods　of　how　to　analyze,　distinguish　and　classify　the　signals　are　also　presented.