On the development of higher order accurate projection methods, the following works are completed in this dissertation: ( 1) The concept of continuous projection method is proposed, which overcomes some difficulties in the accuracy analysis of semi-and fully-discrete projection methods. 在高阶精度投影方法的研究方面,开展了如下工作:(1)提出了连续投影方法的概念,从而避开了半离散和全离散形式投影方法在理论分析中遇到的一些困难。