how to open ssrs report from asp web page using report viewer

You need to separate out the URL to the server, report path and add the parameters to a parameters array.

Here's a sample:

    protected void Page_Init(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        // Set the processing mode for the ReportViewer to Remote
        reportViewer.ProcessingMode = ProcessingMode.Remote;

        ServerReport serverReport = reportViewer.ServerReport;

        // Set the report server URL and report path
        serverReport.ReportServerUrl =
            new Uri("http://<Server Name>/reportserver");
        serverReport.ReportPath =
            "/AdventureWorks Sample Reports/Sales Order Detail";

        // Create the sales order number report parameter
        ReportParameter salesOrderNumber = new ReportParameter();
        salesOrderNumber.Name = "SalesOrderNumber";
        salesOrderNumber.Values.Add("SO43661");

        // Set the report parameters for the report
        reportViewer.ServerReport.SetParameters(
            new ReportParameter[] { salesOrderNumber });
    }
}

Above taken from Using the WebForms ReportViewer Control.