The invention provides a timber transverse shearing strength measurement device and method. The device structurally comprises a timber test piece to be measured, five timber filling blocks, left and right supporting seats, a loading head, and left and right clamping heads. According to the measurement method, a force loaded by a mechanical testing machine is applied to the timber test piece to be measured through the timber filling blocks; the timber filling blocks and a wood member have the same wood properties so that a loading process of a test is very close to an actual stress state of a wood shaft pin, and a testing result can really reflect the transverse shearing strength of the wood shaft pin. The timber transverse shearing strength measurement device and method have the advantages and the effects that (1) the problem of correctly evaluating the transverse shearing strength of the wood shaft pin is solved; and (2) the timber filling blocks which have wood properties the same as those of the wood member are lined among the supporting seat, the loading head, the clamping heads and the timber test piece to be measured, so that the loading process of the test is very close to the actual stress state of the wood shaft pin, and the testing result acquired by the method can really reflect the transverse shearing strength of the wood shaft pin, namely the timber transverse shearing strength.