Although the name of the event is usually understood as a plural possessive (i.e. "day belonging to fathers"), which would under normal English punctuation guidelines be spelled "Fathers' Day," the most common spelling is "Father's Day," as if it were a singular possessive (i.e. "day belonging to Father").

In the United States, Dodd used the "Fathers' Day" spelling on her original petition for the holiday, but the spelling "Father's Day" was already used in 1913 when a bill was introduced to the U.S. Congress as the first attempt to establish the holiday, and it was still spelled the same way when its creator was commended in 2008 by the U.S. Congress.

参见：

1.世界各地的父亲节

http://www.enmajor.com/cn/Html/Go_abroad/Culture/Holidays/367531362.html

2.父亲节的英语介绍、来历

http://www.enmajor.com/cn/Html/Go_abroad/Culture/Holidays/0065923.html