The invention discloses a high-strength building block. The high-strength building block comprises two base plates, one or more inserting slots are separately formed in four surfaces of the base plates, a telescopic tube is arranged between the two base plates, one or more closing rods with a telescopic function is arranged on the outer wall surfaces of the two base plates in a mode of surroundinga circle of the base plates, and the one or more closing rods are arranged surround a circle of the two base plates and enclosed to form a rectangular building block body. The high-strength buildingblock can be adjust the length according to needs when used without destroying the building block, the use is more flexible, upper connection strength and lower connection strength are good when the high-strength building block is used, a hollow pouring cavity is formed inside the high-strength building block, an upper building block and a lower building block are assembled and can be well connected through concrete, and the connection strength of an entire wall body is increased.