As one of the three primary colors, deep-blue luminogens play an important role in the organic light-emitting diodes (OLED) full-color display field, however, luminogens with narrow-band emission is still relatively lacking. In this work, we selected 9,9-dioctyl fluorene as the π-bridge skeleton, dimethylfluorene-substituted methoxylphenylamine as the donor, to prepare a completely symmetrical D-π-D structure PFCP-2. The material utilizes 9,9-dimethylfluorene to extend conjugation of the donor, weakened the charge transfer (CT) state of the whole molecule and ensured narrow-spectrum emission. In addition, methoxy provides suitable hindrance to suppress intermolecular interactions and redshift of emission in solid-state. Thus, non-doped OLED based on PFCP-2 realized the commission International de L'Eclairage (CIE) coordinate of (0.17, 0.11) with stable EL spectrum at 428 nm. More importantly, OLED based on PFCP-2 exhibit narrow full width at half maxima (FWHM) of 35 nm, which is one of the narrowest FWHM of deep blue OLEDs reported so far.