Background: People with post-stroke moderate to severe aphasia commonly receive speech-language therapy (SLT). However, the outcomes of SLT sometimes is limited. Augmentative and alternative communication (AAC) has been reported as an effective treatment approach to improve communication effectiveness, language performance, decreasing depression, and improving quality of life for this population. However, little evidence has demonstrated the use of AAC intervention (AACT) in early recovery from people with post-stroke aphasia in in-patient rehabilitation settings. Besides, only a few studies use a randomized controlled trial (RCT) to compare AACT with SLT to date. The present study focuses on the effect of including AACT in regular SLT for people with post-stroke moderate to severe aphasia (PWAs) in an in-patient rehabilitation setting. The present study aims to compare the potential effectiveness of AACT combined with SLT on communication effectiveness and language recovery with SLT alone for PWAs in in-patient rehabilitation settings.Methods: We strive to include 30 PWAs, enroll in an in-patient program, a single-blind, randomized controlled trial with two parallel groups, and a 2-week follow-up. Patients receive a one-hour treatment session, including either both AAC and SLT or SLT alone daily for ten consecutive sessions. Three assessment points include baseline, after intervention sessions, and after the 2-week follow-up to compare the two groups' intervention effectiveness. The primary outcome measure is the score differences on the Communication of Basic Needs of Functional Assessment of Communication Skills for Adult (FACS) pre- and post- intervention. The secondary outcome measures include the results of the Chinese Standard Aphasia Battery (ABC), the 10-item Hospital version of the Stroke Aphasic Depression Questionnaire (SADQH-10), and the Stroke-Specific Quality of Life Scale (SS-QOL) as well as a patient and caregiver satisfaction questionnaire.Discussion: This RCT of AACT in an in-patient rehabilitation setting will contribute to new scientific evidence to the field of aphasia rehabilitation in early recovery during the in-patient period. The paper describes the trial, which will explore the effect of combining AACT and SLT and SLT only, our choice of primary and secondary outcome measures, and proposed analyses. The study results will provide information for implementing AACT in the regular in-patient SLT of future RCTs.Trial registration: This trial is registered in the Chinese Clinical Trial Registry database (ChiCTR) as ChiCTR2000028870. Date registered: 5 January 2020.