Hello!

Is it correct to say He watches sport on TV or he watches sports on TV. What is the difference?

2 answers

Sports is plural, indicating more than one sport.
PsyDAG is right. "Sports" is plural.

If you are watching one sport on TV, though, you should just name the sport: "I'm watching soccer on TV." But if you're referring to watching all kinds of sports on TV in a general sense, then you use the plural and you don't need to name them.