I dont know why suddenly Suddenly become like this.How to fix it?

Not sure what you're trying to show here... Everything looks okay to me.

urm the colour is wrong.I remeber that the right colour is orange not grey.

Sometimes, particles will turn gray like that if there are too many things to render on the screen. Usually, a restart will fix that issue.

I have restart a few times.But its still turn grey,

Likely caused by some other mod breaking rendering somehow, nothing can be done about this.