Police sources say suspected terrorists fired at and injured Abdul Qayoom outside his home in Barzullah area of Srinagar city.
Mr Qayoom was shifted to a hospital where he was operated upon. Doctors say the PDP leader is stable but his condition remains serious.
Police say gunman fired three bullets at Mr Qayoom from close range.
Earlier in the day, five civilians were injured when terrorists threw a grenade towards a police camp at Imam Sahib in Shopian district. The grenade missed the intended target and exploded on the road.