Taiwanese people do not use the Internet as much as Japanese people do.

Or:

Taiwanese people use the Internet less that Japanese people do.

Or:

Japanese people use the Internet more than Taiwanese people do.

I’ll fix it for you.

“Most Taiwanese people use the Internet less than Japanese people”

or

“Most Taiwanese people don’t use the Internet as much as Japanese people.”

I had to rearrange the sentence structure there, yours was a bit irregular.

For future reference:

You should capitalize races, such as Taiwanese and Japanese.

It is better to use “do not” than “don’t” because it is more clear.

The “Internet” should be capitalized, because it is a proper noun.

You should not use the “don’t use” part, instead do “less than”, so it’s “use the Internet less than”. It sounds much better.

Do not use “the Japanese people” the “the” is incorrect.

There you go, and good luck!

Fewer Taiwanese people use the internet than Japanese people.

or More Japanese people use the internet than Taiwanese people.

Taiwanese use the internet more than Japanese.