Online identification of orifice bluntness was put forward, and specific solutions was given. Orifice discharge coefficient of CFD simulation on normal condition and bluntness conditions were compared with GB/T 21446—2008 to verify the validity of the simulation. To achieve the identification, in the rear of the flange pressure points (P1, P2) another pressure point P3 was installed and the differential pressure ratio factor (η) was calculated. The factor reflected the degree of distortion of orifice plate flow field relative to the normal condition, which was the ratio factor indirectly reflected the degree of bluntness. The best position of pressure points P3 was determined by the analysis of simulation results, and the experience formula about the ratio factor with bluntness was further concluded. Through the formula, online identification of bluntness could be realized. The effectiveness of the identification algorithm was verified through real flow experiments. The error of calculated value was within ±1.0% for sharpness correction coefficient (bk), which proved that the algorithm was practicable in engineering. 