A universal equation of state for solids is proposed. The equation exactly accounts for the cohesive energy; no physically incorrect oscillations exists, and its action is correct in both high pressure and expanded regions. The new equation and several typical equations in literature are applied to 15 alkali halide solids, and one alkaline earth oxide. The results show that the new equation can well fit experimental data, and can give correct cohesive energy. The parameters determined from the Vinet and Morse equations are sensitive to the data range, whereas the new equation is not . This implies that the applicability of new equation is better than the Vinet and Morse equations.