我觉得是可以的，你转的是以前contribute的，相当于一个distribution，要补交税

"A backdoor Roth is a strategy for people whose income is too high to be eligible for regular Roth IRA contributions. You simply roll money from a traditional IRA to a Roth. There are no income or contribution limits — that is, anyone can convert any amount of money from a traditional to a Roth IRA."