In the early seventies, the supply of secondary school places in Yuen Long was severely outweighed by its demand due to the population growth. Secondary school students in Yuen Long and villages had to necessarily undergo lengthy commutes and continue their studies in Kowloon and Hong Kong for a long time. The situation aroused the attention of the late Mr. Chiu Lut Sau, Certificate of Merit for Service Rendered from Queen Elizabeth II, Serving Brother of the Order of Hospital of Saint John of Jerusalem, J.P., M.B.E., O.B.E, who had always shown his deep concern for educating the young people of Yuen Long. He made repeated appeals to the Education Department to build an additional standard-size government secondary school in Yuen Long to satisfy this dire need. In particular, he hoped that the new school would prepare students for tertiary education. To help expedite the implementation of the school project plan, the late Mr. Chiu generously donated $1 million towards the building and equipping of such a school. In October, 1976, extraneous circumstances had brought about a deferment of progress. The Education Department finally decided to proceed with building a government secondary grammar school at 7, Tai Yuk Road, Yuen Long, and the school was to be named as the “Chiu Lut Sau Memorial Secondary School”. The co-educational School was open to classes in September 1979, and the official ceremony was held on 30th, January 1981 with the guest of honour Governor Sir Murray Maclehose.

The opening ceremony of CLSMSS on 30th Jan., 1981, with Sir Maclehose being the Guest of Honour Chiu Lut Sau Memorial Secondary School".