A lean premixed-prevaporization combustor (PPL-1) for a 100 kW automotive ceramic gas turbine has been developed to meet the Japanese emission standards for passenger cars without using an aftertreatment system. The design of a fuel injector and a prevaporization-premixing tube (PP-tube) in the PPL-1 combustor is a key subject for promotion of evaporation of fuel spray. The Sauter mean diameter and the non-evaporated mass fraction of fuel spray in the PP-tube were measured employing a phase Doppler particle analyzer varying inlet air temperature, air pressure, air velocity and swirl number. The evaporation of the fuel spray in the PP-tube was promoted by higher swirl number, air velocity, air temperature and increased atomization of the fuel injector, but was suppressed by higher air pressure and fuel properties such as distillation in high temperature. The characteristics of NOx, CO and HC emissions were measured with a combustor test rig and discussed influences of the evaporation characteristics of fuel spray. Results show that a mass fraction of non-evaporated fuel of less than 10% and lean fuel-air mixtures, i.e. having equivalence ratios from 0.15 to 0.5, reduce the PPL-1 combustor emissions of NOx and CO.