Abstract: The object S5 2007+777 is a classic radio-selected BL Lac object with a kpc-scale extended X-ray jet. The Doppler factor derived from the X-ray emission in literatures is around 13.0, then the intrinsic jet scale will be around 1 Mpc. In this work, we present the jet structure, brightness temperature, proper motion, and other radio properties of this source by collecting the EVN (European VLBI Network) data and VLBA (Very Long Baseline Array) 15 GHz survey archival data. We found that all the EVN and VLBA images show a core-jet structure, and the jet direction is similar in all the VLBI (Very Long Baseline Interferometry) images, but slightly different from the kpc-scale jet. The Doppler factor constrained from the brightness temperature of radio core is around 5.0, smaller than the value estimated from X-ray emission, however consistent with those derived with other methods at radio band. After considering all the VLBI data, we found that there is no a significant proper motion in the source. These results indicate that the Doppler factor of this source may not be very high. However, even with the estimated Doppler factor of 5.0, the jet linear size may still be large, around 0.5 Mpc. This implies that this source probably possesses a very large intrinsic jet, similar to the giant radio galaxies.