I came to t USA in 1980 with a permanent resident card with no experation date shows in my green card but I heard that all green cards has to be change .Is that true .Thank you Connie

Yes... you need to have it replaced if you have an old edition of the card;
Application to Replace Permanent Resident Card (http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=b3f7ab0a43b5d010VgnVCM10000048f3d6a1RCR D)