He said it would improve our English level.

[diamondcutter]

Today our English teacher advised us to keep an English diary. He said it would improve our English level.

(Made by me.)

In this context, does “improve our English level” make sense?

 

[Tarheel]

Yes, especially in a classroom setting. However, I would say it might improve your English.

 

[jutfrank]

It's a very natural and understandable thing to say, yes, but it doesn't really make sense. You can't 'improve' levels. As Tarheel says, what your improve is your use of English, not your level.