That’s a Type-85 APC we bought from China in the 80s to compliment our M113 fleet, some of them are undergoing modernization as of current.
This is an every year occurrence in Thailand, every children’s day, all branches of the Royal Thai Armed Forces throw open their gates and show the unit’s best hardware. In Bangkok, you can watch F-16s and Gripens in airshow at Don Muang, see VT-4, Oplot, BTR-3E1 and other military hardware at the 1st Cavalry in Sanam Pao and meet the veterans in Victory Monument in just a single day. I still remember me as a boy climbing up and down hatches on an M41A3.