Chemical structure and physical properties of Polyetherketone (b-PEK) synthesized from dichlorobenzophenone and sodium carbonate in the presence of silica/Cu salt catalysts have been investigated. After basic hydrolysis, the chemical structure was analyzed by high performance liquid chromatography (HPLC) and mass spectrometric analysis (MS). b-PEK had a few branched structures and was a different from Polyetherketone (1-PEK) which is commercially available or can be synthesized from 4-hydroxy-4'-fluorobenzophenone. b-PEK had good mechanical strength, modulus and fluidity under the high share rate compared with 1-PEK. It was thought to be due to the degree of crystalline or other micro-structure and it observed that the injection molded test specimen of b-PEK had higher crystalline and orientation than 1-PEK by measuring wide angle X-ray diffraction.