how can i delete this outside control points
Short answer: Try to use the command _ShrinkTrimmedSrf
Long answer: The surface is a Trimmed surface meaning there is a base surface that is defined by the control-points you see here. On top of that base geometry are trims; curves that define what parts of the surface are trimmed.
In order too keep it’s shape ( most of) these control-points need to remain as they define the surface and influence it’s shape inside the untrimmed area even if they fall outside the trim boundary. _ShrinkTrimmedSrf will purge all control-points that can be safely removed without influencing the shape inside the untrimmed surface.
Alian and Willem many thanks for the answered it helps a lot