By　means　of　theoretical　analyzing　and　experimental　verifying,　two　flaws　in　the　public　verifiable　threshold　proactive　secret　sharing　scheme　proposed　by　Shi　Runhua,　are　found.　First,　the　value　of　threshold　k　can　not　be　trusted.　Second,　the　attackers　can　crack　the　secrets　S　in　terms　of　public　shares　update　algorithm.　At　last,　new　analyzing　methods　for　proactive　secret　sharing　scheme　are　proposed,　which　can　conduct　comprehensive　analysis　of　forward-threshold　secret　sharing　scheme　by　extending　the　completeness　of　proactive　secret　sharing　scheme,　and　the　unidirection　of　shares　updated　algorithm.