The history of the Department of Mathematics dates from the very early years when the University was founded. After joining the Faculty of Science newly formed in 1939 it has since remained a core department of the Faculty, but also offers courses for students in other Faculties. As a mathematics department with the longest history in Hong Kong the Department has throughout the past seven decades produced batches after batches of graduates who either go on to pursue a mathematics-related career or to take up positions in other walks of life, but all of whom benefit from a good solid general undergraduate education in mathematics that nurtures their quantitative reasoning, logical and analytical thinking, meticulous care to work, ability to conceptualize, problem-solving skill and innovative imagination. Among these graduates quite a number join the teaching profession in the tertiary and the secondary sectors, thereby contributing to the education of succeeding generations in the subject. Some of them excel in their own fields to become internationally renowned mathematicians or educators working in academia local and abroad. In the early 1970s the department began to produce its own postgraduates, and numerous students have since obtained their PhD and MPhil degrees at the department.

In research, even in the former days dating from the early 1950s when research was not as emphatically promoted and supported in Hong Kong as it is today, the department has maintained throughout the years a good record in research. By producing a continual stream of publications that appear in international refereed journals, the teaching staff of the Department has earned for themselves recognition in the mathematical community local and abroad. In recent years, with the emphatical promotion and support in research in Hong Kong, the Department has also strengthened in this respect, particularly with the establishment of the Institute of Mathematical Research in 1999. Ever since the 1980s the Department has hosted more than twenty international conferences or workshops, and members of the Department maintain close and constant contact with local and oversea mathematicians and centres of mathematical research. Members actively and frequently participate in international conferences or workshops, and a number of them have been editors/associated editors of renowned international journals, and have also been invited as keynote speakers at international conferences.

In the broader context the Department has been instrumental in the establishment of two mathematical societies, the Southeast Asian Mathematical Society founded in 1972 and the Hong Kong Mathematical Society founded in 1979. In 1995 the Hong Kong Association for Mathematics Education was founded, and almost all the founding members are graduates of the Department from the mid 60s to the mid 80s. Besides the link through this formal organization the Department is for long held in high regard for its commitment in teaching by its many graduates who become school teachers so that a strong network with a congenial cooperative working relation exists, thus forming a bridge between the Department and the local school community. This is further buttressed by annual mathematical lectures and other mathematics-related public events organized by the Department for school pupils and teachers. In this way the Department continues to contribute to the local mathematics education scene long after it furnishes the work force of school teachers themselves.