The Law Department issued a notification to this effect following approval by Governor N N Vohra, an official spokesman said.
Raina's appointment comes a week after Jehangir Iqbal Ganai, who was appointed by the PDP-BJP coalition government, was asked to resign by the Governor.
Jammu and Kashmir is under Governor's Rule since January 8, a day after death of incumbent chief minister Mufti Mohammad Sayeed.