from meilan airport how to go to Tayang Town, Qionghai City, Hainan他洋镇?

You must refer to 塔洋镇 instead of 他洋镇, right? Well then, I suggest u walk to Meilan High-speed Station upon landing to take a train to Qionghai within around 40min. Then take a taxi or a public bus to Dongfeng Road in the city, near which you can catch bus no. 1 to Tayang directly.