BEIJING — Zhao Lin had become accustomed to the single life. But his days and nights were growing lonely, and he decided it was time to find Ms. Right.

That’s how the 78-year-old ended up at the park.

“I have been looking for more than a year,” said Mr. Zhao, a fixture at one of the dozens of senior singles scenes popping up in public parks around China. So far, he admits, the pickings have been slim.

“It’s usually one conversation and that’s it,” said Mr. Zhao, a widower since 1971, in a lament familiar to frustrated singles no matter their age. “There’s no second time. They’ll let you down and there’s no hope. So what’s the point?”

Three decades of economic growth and social change have transformed attitudes of love and sex among China’s elderly. Increasingly single and assertive, the country’s lonely seniors are on the market.