Aiming to improve the transmission performance of indoor visible l ight communication system based on white LED,while focuses on improving the spe ctrum efficiency and reliability,this paper proposes a hybrid modulation scheme that takes both power efficiency and spectrum efficiency into account.In this scheme,carrier-free amplitude-phase modulation (CAP) combines with pulse inte rv al modulation (DPIM),which help the transmitter loads DC offset CAP signal (DCO -CAP) on the pulse slot of DPIM to generate hybrid modulation signal.The recei v er uses the proposed modified hard decision detection algorithm and maximum like lihood detection to complete serial demodulation of hybrid modulation signal.Co nsidering the influence of indoor ambient light,the analytical expressions of bit error rate (BER) and frame error rate (F ER) of two-dimensional DCO-CAP-DPIM scheme in Gaussian channel based on Lambertian illumination model are derived.S imulation experiments verify the accuracy of the theoretical analytical formula and the effectiveness of the modified hard decision detection algorithm.The per formances of DCO-CAP and different hybrid modulations under the same frequency b and utilization are analyzed and compared through numerical simulation for the e xperimental scene of 8m×6m×3m.The results show the reliability of the hybr id two-dimensional DCO-CAP-DPIM modulation system is 2－12dB higher than that o f the single modulation system when the spectrum efficiency is the same while the cor rection algorithm based on hard decision can improve the system reliability by 5dB when the modulation parameters are the same.