The vibrational autoionization stucture of dibromomethane has been investigated in the supersonic beam conditions using ＶＵＶ synchrotron radiation. Based on photoionization efficiency curve of ＣＨ2Ｂｒ2+ in １０５—１２３ｎｍ we have found that the adiabatic ionization potential(IP) of the dibromomethane is １０.２３±０.０１ｅＶ．The thresholds at １０.７８±０.０１ｅＶ，１１.２０±０.０１ｅＶ and １１.２７±０.０１ｅＶ ware identified as the electronically excited states of ＣＨ2Ｂｒ2+,i.e., Ａ（2Ａ2），Ｂ（2Ｂ1） and Ｃ（2Ａ1） states. The discrete peaks with some autoionization features superposed on a step-like structure in the PIE curve of the parent ion were observed in the range of １１５.０１—１２１.１５ｎｍ. The average step width was about ７１６.８±４０.０ｃｍ-1，which was in good agreement with the value of the vibrational frequency of the Ｂｒ-Ｃ-Ｂｒ antisymmetrically stretching motion （ｖ9） of the parent ion ＣＨ2Ｂｒ2+（Ｘ2Ｂ2) which was measured by infrared absorption method. All strong peaks ware assigned to the autoionization, ｎｓ，ｎｐ and ｎｄ Ｒｙｄｂｅｒｇ states converging to various vibrationally excited states of the ground state of ＣＨ2Ｂｒ2+. In addition, the vibrational modes and autoionization structure occurring in the ground electronic state of the daughter ion ＣＨ2Ｂｒ+（Ｘ）were also assigned.