If you go to

menu > Settings > Logins and Passwords > Saved logins

and enter your device PIN

are you able to view them there?

To delete one, individually, you can tap it, tap the menu button on that page, and tap Delete.

I don't know whether there is a faster way to bulk delete them.

thanks, I want a faster way. by the way, I have deleted all passwords in firefox for pc, why firefox for android can't delete them by sync?

Hi

If you have deleted them in your other copy of Firefox, but still have login details set as somethign to be synced, the deletion will be synced to your copy of Firefox for Android.