Abstract: Prefabricated steel-beam structures are becoming a trend in school buildings, and the sound environment of classrooms are of great importance, with reverberation time being one of the important indicators in classroom sound environment design. In this paper, the calculation of reverberation time in classrooms under discrete and non-uniform sound absorption conditions is studied with the aim of obtaining more accurate and applicable calculation methods. Two typical steel-beam structure classroom geometries are chosen, and three types of ceiling beam absorption arrangements are set up in each room. The reverberation times from 125 Hz to 4 kHz octave bands are calculated using five different models and then compared with the corresponding measured results. The differences between the results of different calculation methods and the measured results are analyzed and compared. The results show that the reverberation time spectrum obtained by five different calculation methods have similar trends, but there are significant differences in numerical values. The Sabine formula and Arau method can obtain results that are more consistent with actual measurements, while the Arau method can provide more accurate estimates of reverberation time under various sound absorption conditions.