Under the background of carbon peaking and carbon neutrality, iron and steel industry urgently needs low-carbon reconstruction. Hydrogen direct reduction (usually called "hydrogen metallurgy") is an important research field in the domestic and overseas. Fluidized bed (FB) direct reduction has been the research direction at Institute of Process Engineering (IPE) for more than 60 years. On the occasion of commemorating the 120th anniversary of Professor Chu-Phay Yap's birth, this work reviews and summarizes a series of important achievements on basic researches and industrial applications of FB direct reduction at IPE. In the basic researches respect, the competition of adhesive force and rupturing force for particle sticking, the behaviors of agglomerate fluidization and slow defluidization, the growth mechanisms and sticking characteristics of newly formed iron with different morphologies were revealed; and a series of methods for anti-defluidization were successively established, including particle coating and iron morphology regulation to reduce the adhesive force, and enhance particle motion, particle size increase, using external field forces to increase the rupturing force. Furthermore, several pilot plants with various iron ores were constructed and operated to promote the industrial application of new technologies, including hydrogen FB direct reduction of 100 kg/d iron ore concentrate, 1 t/d vanadium bearing titanomagnetite and FB direct reduction-electric furnace smelting of 2000 t/a vanadium bearing titanomagnetite. Currently, IPE is cooperating with Ansteel Group to establish the world's first FB direct reduction pilot plant of 10 000 t-DRI/a using green hydrogen. This paper aims to commemorates Professor Chu-Phay Yap, Professor Mooson Kwauk and other scientists of the older generation, and also to propel advance of basic theory and technology in FB direct reduction, for promotion of the low-carbon development for the iron and steel industry of China.