The title of the book at first rings with irony - this is a dystopian novel that portrays anything but "paradise". The title also alludes to the promised "worker's paradise" that was disseminated in Communist propaganda, one that never materializes. The blind in this case may well be the Communist leaders who promote a political and economic system that will eventually fail.
As the book progresses, however, we might see the title in reference to the protagonist, Hang. It is only by becoming "blind" to the external circumstances that bestow suffering onto her family - namely history, politics, tradition, and class - that she finally finds freedom and happiness. Finding paradise depends on her ability to look past (or not see) the tragedy surrounding her.