参考

Dim url As String = "http://api.k780.com:88/?app=finance.rate&scur=USD&tcur=CNY&appkey=10003&sign=b59bc3ef6191eb9f747dd4e83c99f2a4"
Dim rqst As System.Net.HttpWebRequest = System.Net.HttpWebRequest.Create(url)
Dim rsps As System.Net.HttpWebResponse = rqst.GetResponse
Dim stm As System.IO.Stream = rsps.GetResponseStream()
Dim reader As New System.IO.StreamReader(stm)
Dim str As String = reader.ReadToEnd
stm.Dispose()
Output.Show(str)

Dim data As object
Dim JscriptCode = "function toObject(json) {eval(""var o=""+json);return o;}"
Dim ScriptControl = CreateObject("MSScriptControl.ScriptControl")
With ScriptControl
    .Language = "Javascript"
    .Timeout = -1
    .AddCode(JscriptCode)
    data = .Run("toObject", str)
End With

Dim d As Double = data.result.rate

msgbox(d)