A two-way terahertz beam steering device is designed and proposed based on phase change material vanadium dioxide(VO2) and coding metasurface technology. At 0.7 THz, by giving the device thermal excitation to control the phase transition state of VO2, the device can be switched between two working modes of reflection and transmission. When the device temperature is higher than 68 ℃(the phase change temperature of VO2), the VO2 turns into metallic state, and the device works in reflection mode which means the device efficiently reflect and split the incident wave into several beams with similar energy and different directions. Under normal temperature, VO2 is in insulating state, and the device works in transmission mode to transmit terahertz wave efficiently. The dynamic control of beams in both directions of reflection and transmission makes the device itself no longer an obstacle to transmission of reflected or transmitted waves. This dynamic two-way control of the terahertz beam is very useful in terahertz wireless communication scenarios.