In this paper, an exciton-photon model is created in an optic microcavity, and then in Bose condensation (BC), the variations of chemical potential range and number density of particles with temperature and position are studied in cases: constant width and varying width. Taking a semiconductor optic microcavity GaAs as example, the influence of temperature on BC is analyzed. The result shows that the range of chemical potential is related to dielectric function and microcavity width, while the number densities of photons and excitons and the sum of both particle numbers are related not only to them but also to temperature. The theoretical temperature of BC of GaAs is close to the experimental value. The densities of photons and excitons are almost equal, and their distributions are restricted to r=0 when BC occurs. With the reduction of temperature the number densities of both particles increase and their distributions expand, and the number of photons is more than that of excitons no matter how the width of optic microcavity changes.