Jamaica's Fraser-Pryce got away quickly in the 100m final and never looked like being caught by home favourite Dina Asher-Smith, winning in a time of 10.78 seconds.
World 200m champion Dafne Schippers was disqualified after a false start at the Diamond League event.
"It's a long season and I've been training and training," said 32-year-old Fraser-Pryce, who won Olympic 100m gold in 2008 and repeated the feat on the same London track four years later.
"To come out here and run 10.78 is a fabulous time. I feel good. The aim is to make sure when I get to Doha (world championships) that I'm on point."
No Americans were in the 100m field at the London Stadium because their world championship qualifiers are coming up this week.
Kenya's Obiri, world champion in the women's 5000m, posted a time of 14 minutes 20.36 seconds -- the best of the year so far.
Dutch runner Sifan Hassan, who broke the 23-year-old women's mile record in Monaco last week, had to settle for bronze.
"I am so happy because this is my favourite track and I have done my best and I ran the way I wanted to," said Obiri.
"In the last lap I was thinking, work hard and I said to myself when I went past Hassan: 'let me go and see if you can catch me'. I have been training well and this will help when I defend my title in Doha."
Britain's Lynsey Sharp was a popular winner in the women's 800m, outlasting Australia's Catriona Bisset to win in a time of 1:58.61.
In other women's track events, Jamaica's Rushell Clayton won the 400m hurdles in 54.16 sec.
Germany's Malaika Mihambo won the women's long jump with a leap of 7.02 metres.
Asian 200m record
China's Xie Zhenye set a new Asian record in winning the men's 200m in 19.88sec while Jamaica's Akeem Bloomfield won the 400m in 44.40sec.
"It was amazing because it was my PB (personal best) and a new Asian record, so I'm very happy. I love you guys, I love this track," he said.
"I just told myself to go fast. This gives me a lot of confidence for the world championships."
China's Xie Wenjun won the 110m hurdles in a time of 13.28sec.
World indoor 1500m record holder Samuel Tefera of Ethiopia ran the fastest mile of the year so far in a time of 3:49.45, beating Norway's Filip Ingebrigtsen by just 0.15sec.
The mile is not an Olympic or world championship distance.
Ingebrigtsen, 26, who set a new Norwegian record, is the older brother of 18-year-old Jakob Ingebrigtsen, who finished second in Saturday's 5000m.
Syria's Majd Eddin Ghazal won the men's high jump with a leap of 2.30m, beating world champion Mutaz Essa Barshim into second place, and Sweden's Daniel Stahl won the men's discus with a throw of 68.56m.
Britain's men's sprinters won the 4x100m relay, clocking 37.60sec, the fastest time of the year.
There are Diamond League events to come in Birmingham, Paris, Zurich and Brussels in the lead-up to the world championships in Doha, which start on September 27.