ObjectiveTo measure the operational efficiency and explore the phenomenon of the economy of scale in secondary public general hospitals of China for improving the health service efficiency.MethodsFrom February to August 2019, the data set of two input indicators (the number of employees and actual open beds) and two output indicators (the numbers of outpatients and discharges) in 511 secondary general hospitals of Shandong, Anhui, Shanxi, Hubei and Hainan provinces in 2018 were collected for data envelopment analysis. The analysis processes were three folds: First, the technical efficiency, pure technical efficiency, scale efficiency and scale compensation status of the sample hospitals were calculated respectively. Second, the comparative analysis of efficiency value and scale compensation status was carried out in 5 groups according to the bed scale. Finally, the input and output projection analysis was carried out on the ineffective decision making units.ResultsThe medians of technical efficiencies, pure technical efficiencies, and scale efficiencies of the 511 secondary general hospitals were 0.472, 0.531, and 0.909, respectively. In the 511 hospitals, 493 hospitals (96.5%) were in ineffective state, of which 321 hospitals (62.8%) were in the state of decreasing return to scale. The staff redundancy of the group with beds >100 and ≤300 was 23.86%, and its service quantity could be increased by 39.37%.ConclusionsThe overall operating efficiencies are inefficiency in secondary general hospitals of China and the optimal scale of actual open beds is between 300 and 500 beds from the perspective of scale efficiency.