The flame retardant 2-(6-oxido-6H-dibenz[c,e][1,2]oxaphosphorin-6-yl)-methanol (ODOPM) for epoxy resins was prepared by the reaction of 2-(2-hydroxyphenyl)phenylphosphonic acid (HBP) with paraformaldehyde. The syntheses method is simple and can lower the production costs than conventional method. The basic solubilities data of ODOPM in water (303.57 to 361.63) K as required in the new process and in p-xylene (302.95 to 360.65) K as in the conventional process were measured. The solubilities of ODOPM in acetone, ethyl acetate, benzene, and toluene were also measured for comparison.