The role of Article 82 of EC Treaty in the system of EC Competition law is to regulate undertakings which have been found to occupy positions on particular markets, i.e. those firms with extensive market power, such as near monopolies. In common with Article 81, its aim is to prohibit the use of market power to damage effective competition in markets by preventing access to markets or driving out existing competition, as well as to fix prices at higher than competitive level. For intellectual property rightholders, it’s important to recognize that there different degrees of dominance with different legal consequences. Since the whole structure of regulation by prohibition of abuse in Article 82 only applies if there is a finding of a dominance upon a particular market and relevant market as they apply to IPRs with exercise, i.e. refusals to licensing, tie-ins, excessive pricing and predatory pricing. This thesis, basing on Article 82 of EC Treaty, comprises six parts：Chapter One-Introduction; Chapter Two-The analysis of IPRs; Chapter Three-Intellectual property rights and the concept of dominance; Chapter Four-Intellectual property rights and refusals to licensing; Chapter Five-Intellectual property rights and tie-ins, excessive pricing, discriminatory pricing, predatory pricing; and Chapter Six-Conclusions.