Background: These lack a thorough comparison of swept-source optical coherence tomography (SS-OCT) features among different kinds of choroidal tumors and tumor mimics. Methods: This retrospective case series study based on 305 eyes from 298 consecutive patients with choroidal tumors or tumor mimics treated at Beijing Tongren Hospital between July 2019 and March 2024. The diagnostic performance of SS-OCT features in distinguishing malignant tumors were evaluated. Results: The present study included choroidal melanoma (n = 113), choroidal lymphoma (n = 11), choroidal metastasis (n = 9), choroidal hemangioma (n = 92), choroidal nevus (n = 9), choroidal osteoma (n = 32), RPE adenoma (n = 4), choroidal tuberculoma (n = 2), posterior scleritis (n = 2), and choroidal leiomyoma (n = 1). The median thickness and largest basal diameter were 2.9 mm (interquartile range: 2.0-4.2) and 9.0 mm (interquartile range: 5.7-11.3). Among all SS-OCT features, multivariable logistic regression showed optical shadowing (Odds Ratio [OR]=104.1, 95 %CI: 5.33-2028.8), subretinal fluid (<3 mm from margin: OR=100.9, 95 %CI: 2.21-4607; >3 mm from margin: OR=24.2, 95 %CI: 2.14-274.0), and overlying choriocapillaris complete loss (OR=52.3, 95 %CI: 4.85-552.7) highly indicated malignant choroidal tumor. Choriocapillaris loss was more sensitive (0.962, 95 %CI: 0.926-0.992) in identifying malignant tumors than optical shadowing (0.791, 95 %CI: 0.730-0.850) and subretinal fluid >3 mm from the tumor margin (0.714, 95 %CI: 0.639-0.788). Choriocapillaris loss also showed high sensitivity (0.923, 95 %CI: 0.919-1.000) and specificity (0.973, 95 %CI: 0.940-1.000) in identifying choroidal melanoma from choroidal nevus. The appearance of choriocapillaris loss or subretinal fluid >3 mm from the tumor margin showed 100 % sensitivity in identifying malignant amelanotic tumors. Conclusions: Choriocapillaris loss, optical shadowing, and extensive subretinal fluid can be used to identify malignant tumors.