The present invention refers to an improved pharmaceutical composition of diclofenac or pharmaceutically acceptable salt and pharmaceutically acceptable excipients wherein the composition is substantially free of solubilizing agents. By judicially using pharmaceutical excipients other than solubilizing agent, pharmaceutical composition of diclofenac or its salts with rapid and uniform gastrointestinal absorption of diclofenac can be achieved. The composition of the invention can also minimize the controllable side effects of diclofenac.