In existing metro systems, the train ground radio communication system for different applications are deployed independently. Investing and constructing the communication infrastructures repeatedly wastes substantial social resources, and it brings difficulties to maintain all these infrastructures. We present the communication Quality of service (QoS) requirement for different train ground radio applications. An integrated TD-LTE based train ground radio communication system for the metro system (LTE-M) is designed next. In order to test the LTEM system performance, an indoor testing environment is set up. The channel simulator and programmable attenuators are used to simulate the real metro environment. Extensive test results show that the designed LTE-M system performance satisfies metro communication requirements.