L-1 allowes dual intent

我是否可以在回国领取签证前，提交1-140表格的申请？那时候，我的DS-160表格上需要说明在美国是有提交移民申请的。这是否会影响在国内的美国大使馆里L1签证延期的批准？

不会影响。

Certain types of foreign visitors are allowed dual intent, and other categories of visitors are not. Persons with H-1B visas (for specialty workers and their spouses and minor children with H-4 visas), K visas (for fiancees or foreign spouses of US citizens and their minor children), L visas (for corporate transferees & their spouses and minor children), and V visas (spouses and minor children of lawful permanent residents) are permitted to have dual intent under the Immigration and Nationality Act.^[1]

https://en.wikipedia.org/wiki/Dual_intent