"This one was really difficult for me because I've been fighting with a lot of injuries and I also had a problem with my heart. It was really difficult but I'm very happy to have won."
Liu also won gold in the -67.5kg at the London 2012 Games and in the -75kg at the Beijing 2008 Games.
His impairment is the result of polio, which he contracted as a child.
Teenager Li Junsheng beat local favorite Daniel Dias to claim gold in the 100m breaststroke SB4.
The 16-year-old touched the wall in 1 minute, 35.96 seconds, just 17 hundredths of a second ahead of the Brazilian. Colombia's Moises Fuentes Garcia clinched bronze in 1:37.40.
Dias said he was surprised by Li's performance but added that his rival was a deserving winner.
"I confess ... The Chinese surprised me, and all of us. China are also showing the world that they are very strong and we have to lift our game."
Li was diagnosed with cerebral palsy when he was one and took up swimming in 2012.
Chen Junfei leapt a personal best 4.77m to win gold in the women's long jump.
The 24-year-old recored a best jump of 4.77m to beat Australia's Taylor Doyle by 15cm. Poland's Anna Trener-Wierciak took bronze with 4.53m.
Chen also won gold in the 200m T38 at the London 2012 Games.
Wang Yinan grabbed his fourth Paralympic gold medal by winning the men's 100m freestyle S8.
The 26-year-old touched the wall in 56.80 seconds to beat his compatriot Song Maodang by 1.33 seconds. Britain's Craig Josef pocketed bronze in 58.19.
Wang also won the 100m freestyle S8, 400m freestyle S8 and 4x100m medley relay 34 points at the London 2012 Games.
He was born with cerebral palsy, which resulted in an impairment to his right foot.
Liu Jing beat South Korea's Seo Su-Yeon to win gold in the women's table tennis CL 1-2. Liu took the match 3-1 (11-6, 9-11, 12-10, 19-17) in 31 minutes at Riocentro.
It was the 28-year-old's fifth Paralympic gold medal after her singles and doubles triumphs at the London 2012 and Beijing 2008 Games.
Italy's Giada Rossi defeated Thailand's Chilchitparyak Bootwansirina 3-0 in the bronze medal match.
China defeated Iran 5-3 in the final to clinch gold in the mixed team recurve archery event. Italy beat Mongolia 5-1 in the bronze medal match.
Shooter Huang Xing won gold in the P3 mixed 25m pistol SH1 by defeating Sweden's Joackim Norberg.
Huang won the final 7-5 to claim his first Paralympic title at the Olympic Shooting Center. Lee Ju Hee took bronze after beating Australia's Christopher Pitt 7-3.
"It is my first Paralympic Games and first medal and I am very happy and very excited. I have completed my goal and achieved my dream come true," the 30-year-old told the Paralympic News Service.
"It's an honor to win for China. I was very nervous but I think I had a little bit of luck as well."
Huang's left arm was injured at age nine in an accident.
Lin Ping clinched her second Paralympic gold medal by winning the women's 200m individual medley SM9.
Lin touched the wall in two minutes 35.64 seconds, just 20 hundredths of a second ahead of Spain's Sarai Gascon. Britain's Amy Marren took bronze in 2:36.26.
Lin also won gold in the 50m freestyle S9 at the London 2012 Games.
"Never did I think I would win a medal here," the 22-year-old told the Paralympic News Service.
I just wanted to go fast and to pay back my coach. My coach and her husband have been training me for 10 years. We are like a family. For the last year we have had private training together, spending all our time together.
"She never pressured me, just helped me improve and encouraged me. I hope we are together all my life."
Lin lost her right hand in an accident at age four.
And Feng Panfeng won his third straight Paralympic table tennis singles class 3 title by defeating Germany's Thomas Schmidberger three sets to one.
The 26-year-old took the match 11-5, 7-11, 11-9, 11-8 in 27 minutes at Riocentro.
It was his fourth Paralympic gold medal, having won the same event at the Beijing 2008 and London 2012 Games in addition to the team class 3 title in London.
Feng's impairment is the result of the effects of polio.
