In order to improve resource utilization in visible light communication(VLC) /WiFi heterogeneous networks, a dynamic proportional fairness(PF) algorithm is proposed. The algorithm optimizes the user's priority by introducing a compensation factor α. Firstly, the key performance indexes of VLC/WiFi heterogeneous network such as throughput, resource utilization and fairness index are theoretically derived. Then, a VLC/WiFi heterogeneous network system is constructed by using Matlab software for simulation. Finally, the performance of dynamic PF algorithm, PF algorithm and Max C/I algorithm in terms of throughput, resource utilization, fairness and access delay probability is compared. The simulation results show that the throughput of dynamic PF algorithm is higher than that of PF algorithm and much higher than that of Max C/I algorithm. The resource utilization rate of these three algorithms is higher than 0.96. The fairness index of dynamic PF algorithm is about 0.97, which is better than the other two algorithms, and the probability of access delay is lower.