Ones I backup my pictures onto my iCloud can I delete them from my iPhone without loosing my pictures on iCloud?

No. iCloud only syncs your photos across devices. If you delete a picture on your phone, it will also delete in iCloud.

I can't move on, I thought after I backup all my photos and deleted it, it will going to upload it on icloud. it has an important photos there.

If you deleted your photos, go to your recently deleted album to restore.