The invention discloses a pinion-and-rack type biaxial tensile test device. The device is characterized in that it includes an upper mould base, a lower mould base, and four synchronous tensile apparatuses located between the upper mould base and the lower mould base, the four synchronous tensile apparatuses are in cross-shaped distribution, the upper mould base and the lower mould base are connected by two guide apparatuses in diagonal arrangement, and the guide apparatuses are located between adjacent two of the synchronous tensile apparatuses. The upper mould base is fixed on a press machine. The pinion-and-rack type biaxial tensile test device provided by the invention has the advantages of convenient use, simple structure, low cost, small volume and the like, and can fulfill the requirements of biaxial tensile test.