The utility model relates to a rear -projection box belongs to rear -projection demonstration technical field, include box shell, rear -projection curtain, projector, lower high reflective mirror and go up the high reflective mirror, the box for the shell panel concatenation form, the bottom half is equipped with the adjustment support frame, the adjustment support frame is connected with the projector, down the support setting is adjusted in the box under through to the high reflective mirror, go up the high reflective mirror through raising the support setting in the box, the utility model discloses a rear -projection box, secondary reflection is passed through in the projection, can guarantee the integrality of image, realizes the picture maximize in the shortest distance to projected image's is of high quality.