持美国绿卡人在美国到加拿大需要签证吗

不需要
http://www.canadainternational.gc.ca/china-chine/visas/beijing-pekin/visiting-visiter.aspx?lang=eng&view=d
United States of America permanent residents [Green Card holders] who are in possession of their status document or who can provide other evidence of permanent residence in the USA do not require a visa to visit Canada. However, if you have been outside of the United States for a considerable period, you must first confirm your permanent resident status before entering Canada.

楼上如果不懂不熟悉签证，请不要随意回答。
美国绿卡持有者可以免签入境加拿大旅行。

不需要，拿着绿卡就行。

要的。

要的。