PM> Install-Package Spire.XLS

using Spire.Xls;
using System.Linq;

namespace RemoveDuplicateRows
{
    class Program
    {
        static void Main(string[] args)
        {
            //创建Workbook实例
            Workbook workbook = new Workbook();

            //加载示例Excel文档
            workbook.LoadFromFile("测试文档.xlsx");

            //获取指定工作表
            Worksheet sheet = workbook.Worksheets[0];

            //指定需要删除重复记录的单元格区域
            var range = sheet.Range["A1:A" + sheet.LastRow];

            //获取重复的行号
            var duplicatedRows = range.Rows
                   .GroupBy(x => x.Columns[0].DisplayedText)
                   .Where(x => x.Count() > 1)
                   .SelectMany(x => x.Skip(1))
                   .Select(x => x.Columns[0].Row)
                   .ToList();

            //移除重复行      
            for (int i = 0; i < duplicatedRows.Count; i++)
            {
                sheet.DeleteRow(duplicatedRows[i] - i);
            }

            //保存结果文档
            workbook.SaveToFile("删除重复行.xlsx");
        }
    }
}

Imports Spire.Xls

Namespace RemoveDuplicateRows
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            '创建Workbook实例
            Dim workbook As Workbook = New Workbook()

            '加载示例Excel文档
            workbook.LoadFromFile("测试文档.xlsx")

            '获取指定工作表
            Dim sheet As Worksheet = workbook.Worksheets(0)

            '指定需要删除重复记录的单元格区域
            Dim range = sheet.Range("A1:A" & sheet.LastRow.ToString())

            '获取重复的行号
            Dim duplicatedRows = range.Rows.GroupBy(Function(x) x.Columns(0).DisplayedText).Where(Function(x) x.Count() > 1).SelectMany(Function(x) x.Skip(1)).[Select](Function(x) x.Columns(0).Row).ToList()

            '移除重复行      
            For i As Integer = 0 To duplicatedRows.Count - 1
                sheet.DeleteRow(duplicatedRows(i) - i)
            Next

            '保存结果文档
            workbook.SaveToFile("删除重复行.xlsx")
        End Sub
    End Class
End Namespace