We, representing IAHR Asia Working Group(AWG), are pleased to conclude the 2nd IAHR-Asia Symposium on Hydraulic Machinery and Systems (IAHR-Asia 2019) with successful and fruitful academic achievements, which was held on September 24-25, 2019 in Busan, Korea.By this international meeting, current research activities and advanced technologies relating to modern hydraulic machinery were introduced and a more efficient way of sustainable development for our future was discussed together with all participants.This conference has attracted nearly 200 scholars and experts from 8 different countries and regions in the field of hydraulic machinery and systems to share new research results and advanced developments.We are very grateful that Professor Young-Ho Lee from Korea Maritime and Ocean University of Korea presided as a chair, Professor Zhengwei Wang from Tsinghua University of China and Professor Kazuyoshi Miyagawa from Waseda University of Japan as co-chairs over the conference. Thanks for all participants for their attendance and sharing the constructive and fruitful discussions.The conference consists of three main parts: invited lecture, general sessions and special sessions covering a wide range of subjects from hydro turbines, pumps, pump-turbines, small and micro hydropower, computational and experimental technique, cavitation, vibration and fluid structure interactions, ocean energy (wave & tidal, OTEC), design optimization of hydraulic machinery and systems, single- & multi-stage pumps and pump sump model tests (CFD & experiment).It is our great honor that 3 experts gave outstanding and excellent invited lectures: Prof. Xianguo Qian, from the China Dredging Association, China; Mr. Yaowu Xu, from State Grid Xinyuan Company, China; Prof. Bhola Thapa, from Kathmandu University, Nepal.Besides the invited lectures, there were 71 general session presentations as well as 8 special session presentations. Oral speakers and poster presenters shared their latest research results with the audience, the audience actively and enthusiastically participated in by asking questions and sharing discussions. This conference proceeding included 28 accepted articles selected from 157 submissions.We are extremely grateful for organizers, committee members and editors and extend our most sincere thanks to all the authors for their excellent contribution and work and participants for their active attending. Our sincere thanks also go to the IOP Publishing editors and managers for their helpful cooperation during the preparation of the proceedings.On behalf of the Organizing Committee of IAHR-Asia 2019