Was the first temple in the world filmed in Yancheng?

No, it's the North Putuo Temple in Changchun. That's the location of Feng Huacheng's Wind of North Putuo Temple.

Beiputuo Temple is located in Jingyuetan National Forest Park in the southeast of Changchun City, Jilin Province, which is18km away from Changchun City. With a unique geographical advantage, it can be called a pure land in a noisy city. The opening ceremony of Beiputuo Temple, founded in 1996, was held on122 June, 997. Although the time is not long, its popularity is very high, and the incense is at its peak during Buddhist festivals. Pilgrims linger in the meantime, and tourists are in an endless stream. Being in a land of treasure, I feel beautiful in peace and kind in freshness.