Objective To investigate the clinical features, chest imaging manifestations, pathological changes, diagnosis and treatment of sarcoidosis with pleural effusion as the initial manifestation, and to analyze the possible causes of misdiagnosis, so as to help clinicians improve their understanding of sarcoidosis with pleural effusion as the initial manifestation, and reduce the rate of clinical misdiagnosis and missed diagnosis. Methods The general data, clinical manifestations, imaging examinations, pathological findings and outcomes of 4 patients with sarcoidosis with pleural effusion as the first manifestation admitted to Ningxia Medical University General Hospital from January 2019 to December 2020 were retrospectively analyzed. Results Out of these patients, 3 were female and 1 was male, with an average age of 50.3 years. The main clinical features were cough, expectoration, chest tightness, shortness of breath and other common respiratory symptoms. Chest CT indicated right pleural effusion. After admission, closed thoracic drainage, tracheoscopy, thoracoscopy, pleural biopsy and cervical lymph node biopsy were performed to obtain pathology. Combined with imaging and pathology, diagnosis was made. After hormone therapy, symptoms and imaging were improved. Conclusions Sarcoidity-related pleural effusion is relatively rare as the first episode, with no specific clinical symptoms and no specific physical and chemical properties of pleural effusion. Non-caseous granulomatous lesions can be found pathologically, and the diagnosis needs to rely on clinical, imaging and pathological comprehensive judgment.