By "Watch Hollywood blue films" I am guessing you are looking for adult movies, what I'm not too sure about is the Hollywood part.
I guess there might be some adult entertainment studios based on Hollywood, but for the most part, I think prices in that part of town have driven the "adult industry" into more affordable corners of California.
Where to watch Hollywood blue movies
It's also a strange question because hardly anyone refers to movies depicting two (or more) adults having sexual intercourse as a "blue movie" any more.
In fact, I looked up the etymology of the term "blue movie" and once suggestion was the term originated from a series of slightly racy French literature:
Nowadays, the term blue movie refers to sex movies - and is a slang term mainly used in India, Sri Lanka, Nepal and Pakistan.
"According to Green's Dictionary of Slang, in the eighteenth century itinerant Parisian booksellers covered their seditious or obscene material with blue paper; the first citation for blue meaning obscene comes from 1818."
Viewing these types of movies online is pretty easy unless you're inside some sort of secured local internet or blocked from accessing these type of sites because of a fire wall or other browsing safety measure.