During the 28-minute video, al-Zawahiri said the slain al Qaeda leader, "terrified America when he was alive and continues to terrify the country in death."
Al-Zawahri, who is Egyptian, is now considered the operational head of the terrorist group. He is thought of as a less charismatic figure who lacks bin Laden's ability to bring together the many nationalities and ethnic groups that make up al Qaeda.
Al-Zawahri praised bin Laden and criticized the U.S. for burying bin Laden at sea after U.S. Navy SEALs killed him in Pakistan in the May 2 raid. He also lashed out at the Pakistani government, saying traitors and corrupt politicians played a role in bin Laden's death.
Al-Zawahri warned that an international community of Muslims will seek and destroy America and its allies.
"Our brothers who are working in Islam in all places, I tell you that our hands are extended to you and our hearts are open to you, so that we can work together to make Allah's word the highest and to make Islamic law in Muslim lands the ruler, not the ruled," he said, wearing a white robe and turban with an assault rifle leaned on a wall behind him.
The message included five poems of praise for bin Laden, portraying him as honest and noble. Al-Zawahri ended his message by saying bin Laden will remain a "source of horror and a nightmare chasing America, Israel and their allies."
Meantime, counterterrorism officials that have been analyzing the trove of material from bin Laden's compound are getting a lot of leads. They've found information in a handwritten journal as well as on computers that has given valuable information on how al Qaeda operatives think and work.
The U.S. is tracking new possible terror targets and stepping up surveillance of operatives once considered minor.
"While we continue to exploit the materials seized from bin Laden's compound, we know that al Qaeda remains committed to attacking the United States," said CIA Director Robert Mueller.
Mueller testified before the Senate Judiciary Committee, saying the FBI is transforming into a threat-based, intelligence led agency. His decade long term is due to end this year. The committee is considering legislation that would allow him to stay on the job for two more years at the request of President Barack Obama.
"President Obama spoke of the ongoing threats facing the United States, as well as the leadership transition at other agencies," said Vermont Senator Patrick Leahy. "He asked us to join together in extending director Mueller's leadership for the sake of our nation's safety and security."
Intelligence experts working around-the-clock have translated and analyzed about 95 percent of the materials seized from bin Laden's compound. They've found sequences of numbers leading to al Qaeda contacts. They expect to finish in the next couple of weeks.
The Associated Press contributed to this story