自己已经找到答案，以移民局为准。下面是移民局的说法
have had your skills assessed as suitable by the relevant skills assessing authority and, unless exceptional circumstances apply, have at least three years full-time work experience in the occupation before the visa application is lodged. A list of assessing bodies can be found in the Employer Nomination Scheme Occupation List (ENSOL).
而且没有提到必须多少年之内多少年工作经验一说。
department will assess your visa application against one of the following:
• you have been working full-time in Australia in the nominated occupation while
holding an eligible temporary residence visa (visa subclasses 457, 418, 422, 428, 421,
444 or 461) for at least the 2 years immediately prior to the lodgment of your visa
application, and that you have spent at least the last 12 months employed with your
ENS sponsor.
• you have a satisfactory skills assessment from an Australian assessing authority
which is relevant to your nominated occupation and you have at least 3 years of postqualification
work experience in your nominated occupation. You do not need to
have the necessary period of work experience if you can demonstrate that exceptional
circumstances apply. Additionally, the skills assessment criterion may be satisfied
if you have already been fully assessed by the relevant registration body for any
mandatory registration, licensing or professional membership requirement for your
nominated occupation.
• you have been nominated for a position with a base salary specified by legislative
instrument that is at least equivalent to the salary for a highly paid executive position.