Yes, you need to apply a single-entry L visa to chinese mainland.

yes, you need a single-entry visa to Beijing, China. It is advisable for you to apply for single-entry L visa in USA. First, prepare the below documents:
1.A valid passport as well as a copy of its information page: Your valid passport must have at least six (6) months of remaining validity and at least one blank visa page in it.
2.Application form: One completed Visa Application Form.
3.Photo: one recent photo of 2x2 square inch (black & white or color is acceptable) glued or stapled on the application form.
4. Sometimes, the hotel reservation or round-trip flight tickets are also required.

.You may submit the application to the Visa Office of the Embassy or Consulate -General which holds consular jurisdiction over the state where you reside;
2.If you cannot come in person, you may entrust someone else or a travel/visa agent to drop off your application at the visa office of the Embassy or Consulate -General which holds consular jurisdiction over the state where you reside;
▲No appointment is required.
▲Mailed applications are not acceptable and will be returned.
Ⅲ.Processing Time
1.The regular processing time is 4 working days.
2.Express service: 2-3 working days processing,additional fee of $20 will be charged per visa.
3.Same day rush service:emergency only, additional fee of $30 will be charged per visa (applications shouldl be submitted before 12:30pm, and may be picked up between 2:30pm-3:00pm on the same day).