We have fabricated the crosslinked Langmuir-Blodgett (LB) films using amphiphilic phenol, p-hexadecoxyphenol (p-HP), which can form polyion complexation with formaldehyde at the air-water interface. The conductivities of p-HP LB films are as follows: heat-treatment of 1 % formaldehyde subphase (3.76x10(-15)similar to4.76x10(-15) S/cm)<1% formaldehyde subphase (7.36x10(-15)8.34x10(-15)S/cm)1.74x10(-14)S/cm). Also, relative dielectric constants of p-HP LB films were reduced from 5.76 similar to8.23 (pure water) to 2.47 similar to2.73 (heat-treatment of 15 formaldehyde subphase).