My baby still jaundice at 7 weeks he feeds well an poos well?

See doctor. This could be very serious. Take the child to the pediatrician or to emergency immediately.
Check bili level. The best thing for you to do is to ask your pediatrician to check the conjugated and total bilirubin level. This will help determine if the jaundice is benign or the jaundice is a sign of a more serious condition in the liver/biliary system. If the conjugated bilirubin is high, then your pediatrician should order more tests to determine the cause.
Mgt. If your baby is beast fed late feeding related jaundice may be the cause. If the baby is otherwise well, an evaluation at the eight week check up may be completed.