CPB President Mujahidul Islam Selim also demanded that the 'political offenders' of that time be punished.
He termed Aug 15 'a day of betrayal and resistance' while speaking at a programme on Friday at Dhaka's Paltan.
"What happened on Aug 15 (in 1975) was not a criminal offence, it was a political offence. Lessons should be learned from that," he said.
In Aug 15, 1975, architect of Bangladesh's freedom Bangabandhu Sheikh Mujibur Rahman, along with most of his family members, was assassinated by a group of disgruntled army officers at his Dhanmondi residence in Dhaka.
Addressing the government, Selim said, "Many domestic and foreign intelligence agencies declassify their secret documents after 30 years. I would like to ask you (the government) to make Aug 15-related documents public and try the political offenders of the time."
The Aug 15 resistance was yet to end despite executions of several killers of Bangabandhu, he said.