In order to obtain analytic theory of 1D photonic crystal, multi beam interference theory is used. Analytical formulas of total reflection tunnel effect frequency of 1D photonic crystal is deduced. Physical mechanism of total reflection tunnel effect of 1D photonic crystal is explained. Using the analytical formulas change rule of total reflection tunnel effect that response curves of frequency versus cycle number and incident angle and optical thickness are studied. Transmission matrix method and analytical method is compared and their results are the same, which indicates that analytical method is the right way. Analytical theory to analyze variable relation is convenient, it makes up deficiency of numerical calculation method of 1D photonic crystal.