It was founded in 1953 by Pin Malakul as Secondary educators’ training department, Demonstration Unit, Triam Udom Suksa School (Thai: หน่วยสาธิต แผนกฝึกหัดครูมัธยม โรงเรียนเตรียมอุดมศึกษา),[3] making it the oldest demonstration school in Thailand.

Patumwan Demonstration School's campus is adjacent to Chulalongkorn University and Triam Udom Suksa School on Henri Dunant Road, Pathum Wan District in the heart of the city's commercial district.

In the junior years (mathayom 1–3) the syllabus is uniform for all the students, but in the senior years (mathayom 4–6) the school's syllabus is divided into four programs with different subjects: The difference between science–mathematics and art programs is that art programs do not include science subjects in the syllabus.

Programs are chosen by the student entering Mathayom 4 and can't be changed until graduation.

The programs are aimed to aid the students during their university periods, even in the stage of entrance preparation.