Dynamic time-division duplex (D-TDD) transmission in small cell networks have been emerged as one of the promising solutions to support the asymmetric traffic requirements in the next generation cellular mobile communication systems. On the other hand, the backhaul, which carries the traffic between base stations (BSs) and the core network, has great influence on providing reliable and timely connectivity. In this work, we study a two-tier D-TDD network taking the random locations of devices, packet arrival process, scheduling, interference, and backhaul into consideration to understand the influence from backhaul to uplink (UL) and downlink (DL) mean packet throughput per UE (MPT for short). We use an approximate method to derive the interference and successful transmission probability via stochastic geometry, and then achieve the mathematical derivation of DL and UL MPT with different kinds of backhaul using queueing theory tools. Based on the simulation results, we verify the accuracy of our analysis and explore the impact of the service parameters and backhaul.