I did experiments and I determined, when I create instance of Metafile by constructor, like that:
Metafile mFile = new Metafile("Symblo.emf");
properties Size and Resolution are incorrect. That's why image drawing not antialiase.
For getting correct properties of metafile I serialized and deserialized instance.
And second moment, InterpolationMode can be set to HighQualityBicubic:
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;