利用孔径大小为2.32 mm的16阵元换能器，搭建了一套16通道的内镜超声相控阵成像实验系统。在此基础上提出了一种适用于内镜成像的相控阵成像算法(PAI)，该算法利用延时和叠加算法(DAS)取得扫描线数据，再利用合成孔径技术中的相干样点叠加，得到高分辨率图像。该相控阵成像算法实现了发射和接收的动态聚焦。经FieldII仿真和内镜探头超声成像实验验证，与延时和叠加算法以及动态接收聚焦算法（DRF）相比，图像的理论横向分辨率分别提高了93.68%和17.5%，实验获得的实际横向分辨率分别提高了92.78%和14.69%，验证了相控阵成像算法和实验系统的可行性。

With a 16-element transducer whose aperture size is 2.32 mm, an experimental endoscopic ultrasonic phased array imaging system which has 16 channels is constructed. A novel phased array imaging algorithm (PAI) is proposed. The algorithm applies the image lines obtained by the delay and sum algorithm (DAS) as input data, and takes advantage of the synthetic aperture imaging which picks out the coherent samples of the recorded echoes and sums these samples. The algorithm finally obtains a high resolution image. The algorithm is dynamically focused in both transmission and receiving. With FieldII, the results of simulation indicate that PAI can increase the lateral resolution by 93.68% and 17.5% respectively, compared with DAS and dynamic receiving focusing algorithm (DRF). The experimental results indicate that PAI can increase the lateral resolution by 92.78% and 14.69% respectively, compared with DAS and DRF. The simulation and experiment finally verify the feasibility of the phased array imaging algorithm and the experimental system.