As a novel combustion technology, flameless combustion is attractive to achieve highly efficient and low NOx utilization of fuels. In this paper, a new method to realize flameless combustion of pulverized coal based on coal preheating technology was adopted. Experimental research on flameless combustion was implemented with pulverized coal in a 30 kW coal preheating and combustion test rig. In the study, coal preheated characteristics, combustion behavior, and the formation mechanism of NOx are discussed. The results show that the temperature of pulverized coal can be preheated up to above 850 degrees C, and most of the volatiles are released during the preheating process. Only 33.90% of the fixed carbon in pulverized coal is converted into coal gas and most remains in the high temperature coal char, and 91.14% of the fuel-N released from pulverized coal is converted to N-2. Stable flameless combustion can be achieved with preheated fuels in the down-fired combustor, and no obvious flame front can be observed through the fire-observation windows, and the luminosity is uniform inside the down-fired combustor. The temperature profile in the combustion zone is uniform with normalized temperature fluctuation less than 10%. NOx is generated near the fuel nozzle and then reduced in the main combustion zone, and the NOx emission is 67 mg/Nm(3) (6% O-2). The formation of NOx is inhibited by rational air distribution, and the combustion efficiency reaches up to 96.4%.