The invention discloses a detection device and method of the suspending immersion quality of bricks or building blocks. The detection device comprises a supporting steel plate, an electronic balance and a hanging bracket, wherein the supporting steel plate is fixed on a water pool through expansion screws; the electronic balance is placed on the supporting steel plate; the hanging bracket is placed on the electronic balance; the hanging bracket comprises an upper hanging plate and a lower hanging plate; the two ends of the upper hanging plate are fixedly connected with the lower hanging platethrough two pull rods; and a hook is fixedly connected with the center of the lower hanging plate. According to the detection device and method, the hollow ratio detection of the bricks or building blocks can be realized by combining with an existing electronic balance, and the detection device and method have the advantages of convenient use, low detection cost and reliable detection result.