This paper analyzed the characteristics of the transmitted light of SPSC by a numerical model and simulation program. The measured daylight illuminances during the summer of 2016 were combined with the numerical model to assess the efficiency of this separate natural lighting system. The results showed that the average efficiency of the emerging sunlight that was transmitted from the undersides of the sunlight collector during the day were more than 64% for SPSCs with both a 70 degrees apex and a 110 degrees apex. The measured results showed that the average sunlight illuminance was more than 80 kLux under both clear sky and scattered sky conditions during the day at New Taipei city during the summer of 2016. This study also evaluated the splitting ratio of light beam when daylight illuminating different apex SPSC at different time. The distribution of the incident sunlight of an SPSC could improve the flexibility of using solar energy in separate hybrid natural lighting systems. (C) 2019 Elsevier Ltd. All rights reserved.