We use precise point positioning (PPP) technique to process the Global Navigation Satellite Systems (GNSS) data of 10 continuously operating reference stations (CORS) in Vietnam during the period 2019-2022. PPP processing results show that the time series of the North, East and Up components of CORS fluctuate with a period of approximately 1 year. After modelling this variation using a sine function with a fixed period of 351.6 days, we calculate the mean displacement velocity of the CORSs according to the North, East and Up components as follows: (-9.2, +29.5, -4.6) mm/year. The general movement direction of all CORSs is East-Southeast. In which the North, East and Up components of 3 big cities Ha Noi, Da Nang and Ho Chi Minh city are (-9.1, +32.7, +1.0) mm/year, (-9.1, +30.5, -6.0) mm/year and (-7.9, +28.4, -1.9) mm/year, respectively. Compared with the period 2016-2018, the velocities of the tectonic plate change less than 4 mm/year in the horizontal component, and 8 mm/year in the Up component. We have processed three more International GNSS Service (IGS) stations in Thailand (CUSV) and China (HKSL and KMNM) for testing. Our results are consistent with JPL at 1 mm/year in the horizontal and 2 mm/year in the Up component.