The invention discloses a device and method for testing dynamic mechanical properties of materials under tensile/shear combined loading. The device comprises an impact mechanism, an impact bar, an incident bar, a transmission bar and a strain signal acquisition device, wherein a sample is installed at one end of the transmission bar and a buffer is installed at the other end of the transmission bar; the impact bar impacts one end of the incident bar under the impact of the impact mechanism device; the other end of the incident bar impacts the sample; an image acquisition device is installed at one side of the sample; strain gauges are installed on the incident bar and the transmission bar and are connected with an acquisition card; the acquisition card is connected with the signal display device.