Thai citizens holding ordinary passports can enter China without a visa for a stay of up to 30 days, with a cumulative stay of no more than 90 days within every 180-day period. This visa-free policy applies to short-term activities such as tourism, business, and visiting relatives or friends. A visa is required if the stay exceeds 30 days or if engaging in other activities (such as work, study, journalism, settlement, etc.). Please note that the policy may change, so it is advisable to confirm the latest requirements before traveling.