Nearly half of the population would leave should conditions deteriorate after June 30, the survey showed.
While only a small proportion hold foreign passports, people believed relatives living abroad would help them escape.
Political instability, loss of freedom and a downturn in economic prospects are the factors which would spark their flight.
'Obviously, Hong Kong people are preparing for a worst-case scenario and will be willing to ask their relatives for help,' said study investigator Dr Sonny Lo Shiu-hing.
'I don't think the Tung Chee-hwa administration should under-estimate this.' The poll showed 45 per cent would leave or seek means to leave if they found the post-1997 changes unsuitable.
Eight per cent had a foreign passport and three per cent were applying.
