Compound parabolic concentrators (CPC) with tubular absorbers are widely used in solar thermal systems because they can achieve the highest concentration without tracking system. Reducing the gap loss is important for utilization of the concentrators. This paper proposes a model with new V-shaped profile at the bottom of the reflector according edge ray principle and established the model, discusses this model about relative concentrating ratio and gap efficiency. A detailed model of the optical efficiency for the solar collector with inner CPC is built, analyzes the parameters of the model, such as geometrical optics efficiency, transmittance, reflectance and absorption ratio, with methods of ray tracing and geometrical optics. For Accurate analysis, the optical efficiency is divided into the beam and diffuse optical efficiency, and incidence angle radial is divided into incidence angle and axial incidence angle, then analyzes optical efficiency of the designed CPC based on the model, concludes how to select the model in accordance with the size of the gap, and proves CPC with the new V-shaped profile has a good prospect. (C) 2016 Elsevier Ltd. All rights reserved.