The construction of an organic microcavity with an organic light-emitting thin f ilm sandwiched between a porous silicon Bragg reflector and a silver film is dem onstrated.The peak widths of the PL spectra are greatly reduced from 83nm to 4nm as compared with those measured from non-cavity structures.The off-resonant opt ical modes are highly depressed.As is always observed from an optical microcavit y,the peak intensity is enhanced,and the peak position shows a blue shift with i ncreasing exit angles.