In this paper,a constellation design method for illumination compatibl e visible light communication (VLC) system based on color shift keying (CSK) modulation and is p roposed, which can ensure the stability of chromaticity and visual brightness while commu nicating using multi-color light sources.Based on CIE 1931XYZ chroma system,this paper pres ents the mathematical expressions of the chromaticity and luminance constraints in CSK co nstellation layout optimization problem.Furthermore,the interior point method is proposed to solve the problem.Since the interior point method requires the objective function to be d ifferentiable,a local approximation method is proposed to make the objective function of CSK con stellation optimization problem continuous.In addition,the interior point method requires that the starting point of the algorithm is strictly feasible.In this paper,a candidate point generation method is proposed to solve the problem.Experimental results show that the prop osed design method can be applied to the constellation design of CSK-VLC system based on co mmercial light-emitting diodes (LED).