Finally i get the solution if anyone need some reference
private string convert_from_unicode(string str,char c)
{
string rtstr = "";
for (int i=2;i< str.Length; i+=6)
{
string str1 = str.Substring(i, 4);
c = (char)Int16.Parse(str1, System.Globalization.NumberStyles.HexNumber);
rtstr += c;
}
return rtstr;
}
private void btn_convert_Click(object sender, EventArgs e)
{
char f = ' ';
txt_result.Text = convert_from_unicode(txt_unicode.Text, f);
}