| Right to defense is the primary right of criminal suspect in the structure of criminal proceeding. That is to say, right to defense is the sum of all litigious rights for criminal suspect. Constitutions of many countries endow criminal suspects with right to defense,which is the most fundamental right of criminal suspect and also the premise of other rights. The history of criminal proceeding’s development is almost equal to that of right to defense’s development. Investigation stage plays a very important role in the whole period of criminal proceeding, and it not only affects the realization and quality of accusation function, but also directly involves the realization of punishment crimes and human rights protection. Investigation stage is the first stage of criminal proceeding and an important step for ensuring accountability for crimes, protection of the innocent and achieving the purpose of criminal proceeding.During the investigation stage, public security department and procuratorial department are responsible for collecting, examining and confirming testimony and taking coercive measures against criminal suspect to prepare for the next stage. It is investigation procedure, instead of judicial procedure, that determines the destiny of criminal suspect and defendant in China. Therefore, the right to defense for criminal suspect in investigation stage is of great importance.In China, the new constitution of 2012 puts the right to defense into the beginning of the investigation stage, which finally defines the principal status of defense attorney as subject of action. However, no matter lawyers’ right to counsel will expand forward or backward from the judicial procedure, it just reflects the formal meaning of lawyers’ participation. At present, defense function of lawyers in China should lie on its essence instead of on its form. While looking throughout the criminal procedure law of 2012 and its related judicial interpretation, we can clearly find that in investigation stage the interpretation of the litigious right of lawyers is just general,lacking concrete laws, regulation and system guarantee, thus it is quite urgent to build up a reasonable system to ensure the validity of lawyers’ litigious right in investigation stage. This thesis is divided into five chapters except for the conclusion part:The chapter one presents basic concepts of effective assistance of counsel. It mainly introduces the content and standard of effective assistance of counsel,characteristics and related abroad experience of defense in investigation stage, based on experience of Anglo-American law system, civil law system and that of other representative countries and regions.The chapter two presents the theoretical foundation for effective assistance of counsel. It carries out discussion from four different perspectives respectively, namely,presumption of innocence, equality between prosecution and defense, procedural justice and proper purpose.The chapter three analyzes the necessity of effective assistance of counsel. Taking the position of investigation stage in criminal proceeding as its entry point, the thesis discusses the necessity of effective assistance of counsel in investigation stage, as well as the position and function of lawyers in investigation stage.The chapter four analyzes the present situation and plight of lawyers’ defense of in investigation stage. It will analyze the difficulty of meeting, the effect of lawyers’defense and the adoption of their advice. Then, in its second section, the cause that leads to such a plight will be interpreted from the perspective of actual practice.The chapter five will discuss the construction of lawyers’ effective defense system in investigation stage, including the completion and guarantee of lawyers’litigious right and related supporting systems in investigation stage. It presents an overall discussion on the probability of building up a system of effective assistance of counsel. |