我反馈一下。有2种临时解决方法
1、Yobo改为下划线
2、使用Padding.Right
rx = new prt.RenderText
Dim xm As String = "张三"
rx.Text = " " & xm & "_"
rx.Style.Font = New Font("楷体", 13) '设置字体
rx.Style.LineSpacing = 150 '1.5倍行距
rx.Style.FontUnderline = True '加下划线
rx.Style.Padding.Right = 1
rx.x = "Prev.Right"
rx.y = "Prev.Top"
rx.Width = "Auto"
doc.body.Children.Add(rx)