Rate splitting multiple access (RSMA) is deemed to be a multiple access technique of the next generation, which is also adopted in visible light communication (VLC) to achieve massive connection and boost data rate. However, how to use RSMA in the multicarrier VLC system remains an open problem. To solve it, an RSMA scheme is conceived for multicarrier VLC system, in which asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) is employed. In the proposed scheme, optical power constraints imposed on the precoding matrix of RSMA are first deduced to meet the lighting requirements for the ACO-OFDM-based VLC system. Furthermore, given the objective of the max-min rate, joint optimization algorithm of the precoding matrix and rate allocation is designed under the optical power constraints to improve the user rate, as well as guarantee the communication fairness. Simulation results have shown that the proposed scheme significantly outperforms the conventional space division multiple access (SDMA) in terms of the spectral efficiency.