Background: The efficacy of art therapy as an adjuvant treatment for schizophrenia remains inconclusive, and variation in the effects of art therapy on schizophrenia by the type of schizophrenia, severity of schizophrenia, type of art therapy, follow-up duration, or different populations has never been systematically assessed. The objective of this study is to systematically evaluate the effects of art therapy on schizophrenia and to determine whether there are some potential influencing factors affecting the effects of art therapy. Methods: Seven online databases will be searched from their inception until June 30, 2022. All the relevant randomized clinical trials (RCTs) comparing art therapy plus standardized treatment versus standardized treatment alone for schizophrenia will be selected and assessed for inclusion. The Cochrane risk-of-bias tool will be used to evaluate the methodological quality of the included RCTs. Review Manager 5.4 will be used to analyze all the data obtained. Mental health symptoms are defined as the primary outcome, and the secondary outcomes include the Global Assessment of Functioning score, quality of life, functional remission, and the level of self-esteem. Subgroup analyses will be performed based on the type of schizophrenia, severity of schizophrenia, type of art therapy, follow-up duration, or different populations. Results: The results will be published in a peer-reviewed journal. Conclusions: This updated systematic review and subgroup meta-analysis will evaluate the effects of art therapy as adjunctive treatment to standardized treatment in patients with schizophrenia and determine whether there are some potential confounding variables affecting the effects of art therapy on the outcomes of schizophrenia patients, thus strengthening the evidence base for the clinical application of this combination therapy for schizophrenia.