Designing the storage lengths for left-turn lanes can significantly influence the operational efficiency of the intersection. However, current design specifications and existing research do not establish a general calcu- lation model of storage lengths, which may produce an unreasonable and hazardous left-turn lane. Based on ve- hicle arrival distribution and queuing theory, this paper analyzed the most unfavorable queuing condition of the left-turn lanes and established the calculation models of storage lengths for left-turn lanes with protected phases and permitted phases. And the calculation models were programmed by C-language which is convenient for de- signers to master. Finally, taking an intersection in Beijing as an example, this paper validated the rationality of the novel models by VISSIM. The simulation results showed that the novel models effectively reduced the delay time of queuing vehicles and improved the operational efficiency of the intersection. Therefore, the calculation models of storage lengths for left-turn lanes may be efficiently applied to the design.