I want to insert a point to the edge,
if I just add a point,the point don't belong to the edge,
How should I implement this in VEX；

Sandabuliu
How should I implement this in VEX

painfully
since there is no insertvertex() function yet
you would need to add point and then rebuild the affected primitives or at least rewire all vertices to include new point and add new vertex at the end
then copy old vertex attributes back to corresponding vertices and interpolate all point and vertex attribs for the new point

in other words not worth the hassle to do it in VEX if you want a proper solution

so instead use PolySplit or TopoBuild/PolyDraw
you can even do it procedurally, just observe split locations syntax on those nodes and generate such string in python or VEX

Sadly it is so hard to do this.

EdgeDivide SOP or Resample SOP