An experimental investigation on condensation heat transfer of R290 with inside diameter of 6.3 mm in horizontal micro-fin tube was presented. Effects of each case on the condensation heat transfer coefficient of R290 were analyzed at saturation temperatures of 40 degrees C, 50 degrees C, and 55 degrees C with heat flux ranging of 3-8 kW/m(2), mass flux ranging of 100-250 kg/(m(2)center dot s) and vapor quality up to 1.0. The results show that the condensation heat transfer coefficients increase with mass flux and heat flux, however decrease with saturation temperature. In addition, compared with the smooth tube, the condensation heat transfer coefficients of R290 in the micro-fin tube increase by about 25%. Comparing the experimental data, the condensation heat transfer correlations of Yu et al. has high accuracy.