An admission method, an admission apparatus, and a communication system are disclosed. The admission method includes: obtaining timeslot utilization efficiency R1 of a first User Equipment (UE) that needs to access a system and timeslot utilization efficiency R2 of a second UE that has accessed the system; judging whether the difference between R1 and R2 is greater than a first decision threshold; and allowing the first UE to access the system if determining that the difference between R1 and R2 is greater than the first decision threshold. The admission method provided herein is applicable to a communication system, and can improve the timeslot utilization efficiency and the throughput of the system.