可以。但一般不能再讀相同專業(yè)的博士學(xué)位。比如，加州大學(xué)伯克利分校就有這么一條規(guī)定：

Duplication of Doctoral DegreeStudents who already hold a doctoral level degree are not admitted and duplication of degree or admission to a lesser degree is not permitted. However, in extraordinary circumstances, the faculty of the department may request an exception from the Dean of the Graduate Division. The department must demonstrate that the second degree field of study and program are distinctly different from that of the original degree, and that there is a professional or scholarly purpose that requires this second degree.

簡(jiǎn)譯如下：

“已經(jīng)擁有博士學(xué)位的學(xué)生，原則上是不允許再申請(qǐng)PhD或比PhD更低階的學(xué)位項(xiàng)目的。但特殊情況下，應(yīng)教師或?qū)W系的申請(qǐng)，研究生部可能會(huì)網(wǎng)開一面。（向研究部）提出這種申請(qǐng)時(shí)，學(xué)系必須提供足夠的證據(jù)證明，這位學(xué)生即將攻讀的專業(yè)領(lǐng)域與之前是截然不同的，而且是非常有必要再讀一個(gè)學(xué)位的?！?/p>

就是說同一專業(yè)領(lǐng)域已經(jīng)擁有博士學(xué)位再來加州大學(xué)伯克利分校讀博士學(xué)位是沒有意義的。但如果不是同一領(lǐng)域的話，是可以的。這種案例每年都有很多。比如國內(nèi)博士是物理，去美國讀經(jīng)濟(jì)學(xué)、數(shù)學(xué)或者計(jì)算機(jī)科學(xué)博士都可以。