In this paper, a biaxial testing machine for the static and low-frequency dynamic tensile testing of biological tissues and soft polymer materials is developed and constructed. The theoretical part of the paper describes static tensile testing as well as ways of measuring deformations with visual methods. Some of the already existing biaxial testing machines used for this purpose are enumerated and describer, with special reference to the different gripping mechanisms depending on the material being tested. Available electromechanical actuators on the market, which would be required for this purpose, were studied and because of their small carrying capacity of transverse forces, it was decided to make our own linear actuator. The necessary parts for the construction of the actuator were calculated and selected. Also, suitable force sensors, as well as cameras were selected so that the deformations in the middle of the sample could be measured by visual methods. Due to the need to immerse biological tissues in a liquid of a certain temperature, it is necessary to place a container with its own lifting mechanism in the middle of the testing machine, for it to be easily removed and rinsed after testing. After making these parts, it is necessary to place the testing machine on a stand made of aluminum profiles. Also, protective covers have been designed to cover the essential parts of the tensile testing machine. Numerical analysis of the construction was carried out, both analytically and numerically in the Abaqus CAE software package. Also, the numerical analysis of the actuator in assembly with construction was carried out, whereby a maximum force of 2kN and a time varying force in the range of 0 to 2kN were used for the axial load of the actuator.