While it was not clear who was behind the attack, al-Hindi was known to have supported government efforts to subdue the rebels and had survived several previous assassination attempts.
The rebels reject the rule of Ali Abdullah Saleh, Yemen's president, as illegitimate, although Saleh is himself a Zaidi.
Their movement, known as al-Huthein after the late commander Hussein Badr Eddin al-Huthi, aims to restore the Zaidi imamate that was overthrown in 1962.
Saleh has led Yemen since the unification of north and south in 1990. Before that he led North Yemen for 12 years.
The parliamentarian's death comes as a government reconciliation body called on Friday for al-Huthein rebels to withdraw from a number of armed positions.
In a statement issued from the Yemeni capital Sanaa, the commission said its members would return to Saada for the implementation of a Qatar-backed reconciliation agreement only once rebels withdrew.
The government body also accused the rebels of "procrastination tactics" - a charge al-Huthein negotiators deny.