I have sponsered for my fiancee's k1 visa, can she come to U.S.A on vistor's visa while waiting for the k1 to be approved?

It is not advisable for your fiancée to enter the US as a visitor during the time that you are sponsoring her for a K-1 visa. If she does not already have the visitor’s visa, she would likely be refused by a US consular officer. In the event that she already has a visitor’s visa, she could have a problem with a CBP inspector at the port of entry upon discovery that her fiancé is a US citizen. Even if she is able to enter the States and ultimately returns to her homeland for K-1 visa interview, a consular officer may take a dim view of her having entered the US during the period of K-1 processing, especially if her stay was prolonged. Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.