To further advance pulverized coal (PC) combustion theory and enable the rational development of horizontal bias combustion technology, combustion experiments were conducted in a 250 kW pilot-scale bias combustion simulator; multiple research means of combustion temperatures, flame spectra, burnout rates of residual solids, and NOx formation were used. A blend of sub-bituminous coal from Indonesia and bituminous coal from Australia was tested. The effects of bias concentration ratio (BCR) on the ignition characteristics of parallel bias PC jets in a reducing atmosphere were investigated. The results indicate that with increasing BCR for parallel bias PC jets, the standoff distance gradually decreased; the peaks of subsequent combustion temperature and visible-light intensity gradually increased; the continuous flame regions became advanced and concentrated; the flame stability gradually increased; the burnout rate gradually increased; the NOx formation gradually decreased, and the ignition characteristics gradually improved. Except at a BCR of 1, the PC ignition of the fuel-rich jet was better than that of the fuel-lean jet, and the continuous flame region of parallel bias PC jets leaned obviously in the direction of the fuel-rich jet. The bias combustion changed the ignition mode of primary air PC jets. There was homogeneous ignition mode at a BCR of 1; when BCR increased to no less than 3, the ignition mode changed to homogeneous-heterogeneous combined ignition, which is beneficial to the PC ignition conditions. Based on the research results in this paper, the recommended BCR for the design of a horizontal bias combustion PC burner is 4-5.