sumanta,
You should use the <PARAM> tags nested within the <APPLET> tags on your HTML page returned to pass the parameters (i'm assuming that you're using a JSP/Servlet to return HTML to the client with the APPLET embedded on the page??). To use the PARAM tags you just specify a parameter NAME and VALUE.
From your applet you can get access to the parameter values using the java.applet.Applet.getParameter(
String) method to retrieve the string VALUE's by NAME.
Akanimo.