The soot/nitric oxides (NOJ trade-off of diesel, biodiesel, and biodiesel-ethanol in a moderate exhaust gas recirculation (EGR) premixed low temperature combustion (LTC) mode is investigated in this study. Compared to diesel, biodiesel demonstrates poorer spray behavior and shorter ignition delay, but its oxygen content results in less soot. Blending ethanol into biodiesel enhances spray behavior, prolongs ignition delay, and further increases fuel oxygen fraction, resulting in a larger reduction in soot. In the moderate EGR premixed low temperature combustion mode, an obvious soot/NO^. trade-off is demonstrated with diesel fuel. The soot/NO^ trade-off is improved by biodiesel fuel and defeated by the biodiesel-ethanol blend. Low soot, low NO^, and high combustion efficiency are achieved with the biodiesel-ethanol blend and proper EGR rate.