| This article takes the view that horizontal mergers between undertakings need to be regulated by the competition law, and indispensably realizes though the assessorial measure-the merger guidelines. Through to introduction on the EC Merger Control Regulation and its Guidelines on the assessment of horizontal mergers, this article discusses the European Union advanced experience to our country's model significance.The first part talks about general theories of horizontal merger and legal regulations on horizontal merger. This part expatiates the conception, types, characteristics and causes of mergers between undertakings. Further, evaluates the correlative economic theories and educes the conclusion that horizontal mergers should be regulated by law and guidelines by economic analysis.The second part introduces in detail the rules of EC Merger Control Regulation and its new merger guidelines. EC Competition regulation roots on the particular social, political and economical background, has its unique thinking origins. The Council of EU has passed EC Merger Control Regulation on January 20th, 2004, and carried on the reformation of entitative and procedural standards. The new standards can effectively inspect the potential anti-competitive situations, and reduce the gaps with America's. Economic analysis has been used more and more to provide available messages to merger regulation. It has been presented more harmonization between EC and America on the analysis structures of horizontal mergers regulation, although they still have some differences.The third part takes the view that the rules of EC Merger Control Regulation and have the important model significance to our country. Firstly, we should establish the economic goals and the standard of effective competition. Effective competition can realize many economic goals, including rapid-renovation, low-cost, low-price, and so on. Secondly, it is proper to establish the direction of economic analysis, as it has a main effect during the process of judging whether a merger needs to be controlled. Thirdly, it's necessary to deal with the relations between industry policy and merger regulation. We should improve our undertaking's international competition ability, but it can not be paid by the derogation of native competition. Lastly, we should enact the legal merger regulations; at the same time it's important to establish the guideline of horizontal mergers to specify the executive standards and analysis structure. |