The invention relates to an organic compound taking fluorene as a core and application of the organic compound in an OLED (Organic Light Emission Diodes) device. The compound is of a structure that the fluorene is connected with a dibenzo five-membered ring combination structure by a carbon-carbon bond; by carbon-carbon bond connection, not only is the chemical stability of a material improved, but also an active position of a branch chain group is prevented from being exposed, and moreover, a whole molecule is of a bigger rigid structure and has a high triplet state energy level (T1); in addition, steric hindrance is great, rotation is not easy, and a three-dimensional space structure is more stable, so the compound has higher glass-transition temperature and molecular heat stability; besides, distribution positions of HOMO and LUMO of the compound are separated from each other, so that the compound has proper HOMO and LUMO energy levels; therefore, after the compound is applied to the OLED device, the luminous efficiency and the service life of the device can be effectively improved and prolonged.