The invention relates to a rotating and positioning device for a laser strap-down inertial measurement unit. The device comprises a rotating shaft, a worm gear, a pedestal, a worm, a coupling, a plug lid, a first bearing, a second bearing, and a stepper motor. The worm gear is disposed between a laser strap-down inertial measurement unit table and a laser strap-down inertial measurement unit box and is fixedly connected with the lower end face of the laser strap-down inertial measurement unit table. The rotating shaft passes through the center of the laser strap-down inertial measurement unit table, the center of the worm gear and the center of the laser strap-down inertial measurement unit box in sequence. The pedestal is fixedly installed to the side of the laser strap-down inertial measurement unit table. The plug lid is buckled onto one end of the pedestal, and the stepper motor is installed at the other end. The worm is disposed on the pedestal, and one end thereof is supported through the first bearing. The plug lid axially positions the worm. The other end of the worm is supported through the second bearing. The part of the worm extending out of the second bearing is connected with the stepper motor through the coupling. The worm gear and the worm are meshed with each other. The device has a simple structure, is easy to control, and can be used for a long time in various different environments.