@veena GollaTry this code in your edit validate rule. This regular expression should work for your use case.

(^[0-9]{2}\\/[0-9]{4}$)

java.util.regex.Pattern pattrn=java.util.regex.Pattern.compile("(^[0-9]{2}\\/[0-9]{4}$)");

java.util.regex.Matcher match=pattrn.matcher(new String(theValue));

return match.find();