The report said the company had been involved in 195 shooting incidents since 2005.
'First to fire'
"In 32 of those incidents, Blackwater were returning fire after an attack while on 163 occasions Blackwater personnel were the first to fire," said Waxman, the chair of the Committee on Oversight and Government Reform, which is investigating the company.
The revelation comes a day before Blackwater faces questions over the September shooting.
Details of the shootings, from Blackwater's own reports, indicate involvement in an average of 1.4 shooting incidents per week since 2005.
Of the total cases, there were 16 Iraqi casualties and 162 incidences of property damage, Waxman said.
The oversight committee will on Tuesday also question senior state department officials to assess whether the growing use of military contractors is undermining US efforts in Iraq.
State department rules say Blackwater's actions should be defensive rather than offensive.
The US Federal Bureau of Investigation (FBI) is sending a team to Iraq to investigate the role of Blackwater in the September 16 shoot-out in Baghdad, an FBI spokesman said Monday.
Richard Kolko, an FBI agent, said the state department requested the FBI to examine evidence in the incident.
"The results of the investigation will be reviewed for possible criminal liability and referred to the appropriate legal authority," Kolko said.
Blackwater, which has received over $1bn from the US government since 2001, declined to comment on Waxman's statement.
"We look forward to setting the record straight on this and other issues" when Erik Prince, Blackwater's chief, testifies before the committee, Anne Tyrrell, a spokesperson for Blackwater, said.
Waxman criticised the US state department's handling of several incidents involving Blackwater.
He accused the department of trying to get the contractor to pay off victims' families rather than investigate.
"It appears that the state department's primary response was to ask Blackwater to make monetary payments to put the 'matter behind us' rather than to insist upon accountability or to investigate Blackwater personnel for potential criminal liability," said the memorandum.
A security guard for Adel Abdul-Mahdi, Iraq's vice-president, was killed by an allegedly drunken Blackwater contractor in December 2006.
The contract worker was then flown out of the country and faced no charges for the killing.
E-mail correspondence from the US embassy in Baghdad to Washington described Iraq concerns over the incident.
"Iraqis would not understand how a foreigner could kill an Iraqi and return a free man to his own country," it said.
The state department's charge d'affaires recommended Blackwater make a "sizeable payment" and an "apology".
Waxman said the state department's diplomatic security said such a move was too much and Blackwater later agreed on a $15,000 payment.
Tom Casey, a state department spokesman, declined to comment on Waxman's specific examples but said the department was "scrupulous" in its oversight of all contractors.
"These are tough jobs and these people often perform heroically in very difficult circumstances," Casey said.
"But at the same time they have to be held accountable for their actions."