In the early seventies, the supply of secondary school places in Yuen Long was severely outweighed by its demand. Secondary school students in Yuen Long had to necessarily continue their study in Kowloon and Hong Kong. The situation aroused the attention of the late Mr. Chiu Lut Sau, O.B.E, J.P., who had always shown his deep concern for educating the young people of Yuen Long, and he made repeated appeals to the Education Department to build an additional standard size government secondary school in Yuen Long to cater for this need. In particular he hoped the new school would run matriculation classes. To expedite the implementation of the scheme, the late Mr. Chiu generously donated $1 million towards the building and equipping of such a school. In October, 1976, circumstances  had changed and the Education Department finally decided to build a government secondary grammar school at Tai Yuk Road, Yuen Long and the school was agreed to be named as "Chiu Lut Sau Memorial Secondary School".

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