Isolators are included in the new earthquake-resistant standard. This article analyses some questions on base-isolators and presents a non-linear dynamic computing-model for the time-history. A corresponding computer program is also compiled. With the program, the earthquake response of a isolated structure including the displacement, acceleration and the shear force of each floor are calculated and compared with those of the same structure without base-isolation. It has been found that base-isolation has important realistic significance in mitigating earthquake disaster effectively and has enormous economic and social benefits. Therefore it is a kind of extremely popularizing and applying new technology.