We have reported that a small amount of long chain n-alkane can drastically change the orientation of copper porphyrin in the mixed LB films. In this study the orientation of porphyrin in the mixed monolayer with and without n-hexatriacontane at the air-water interface was examined. The p-polarized reflection spectrum of the monolayer containing n-hexatriacontane at 45 degrees incidence showed two peaks in the Soret region as in the spectra of the corresponding LB film, suggesting that the orientation of porphyrin in the monolayer is similar to that in the LB film. Further, the lambda(max) and the intensity ratio of these peaks did not change during the compression, indicating that the orientation of the porphyrin is determined before the film compression and preserved during the compression and the film transfer.