Do local people in Taicang need social security to attend public schools?

Don't. According to official website of Taicang Education Bureau, as of July 14, 2023, parents or other legal guardians had household registration in this city. According to their legally fixed residence, they don't need social security when they go to primary schools and junior high schools in their teaching areas at the specified time, and Taicang locals don't need social security when they go to public schools. Non-Taicang students apply for admission, and their parents or other legal guardians have no ownership certificate of residential houses in Taicang and their social security is above 1 year (including 1 year). According to the principle of relative proximity, you can apply for schools in various districts and towns and public designated schools in urban areas.