About user role?

Currently, the first user join the room will be set as moderator.
How can i control this?

If you’re using the public instance at meet.jit.si, you can’t - everyone is set up there as moderators (it doubles as a demo site). If you want to restrict moderator privileges, you can either host your own server or subscribe to https://jaas.8x8.vc, they’ll handle all that for you.

try moderated.jitsi.net

oh right, this is what i want.
how can i did it? i try change role of user but it not work

what do you mean by that ??? you go to the URL, click the button, get 2 URLS, one for users, one for moderatiors. You send the user URL to normal users and you keep to you the secret moderator URL. If you use the moderator URL you are moderator. I don’t see the need to change that.