Egg white tabia mortar(referred to as “egg white mortar”) as the representative of the ancient traditional mortar, was widely used in different areas in China. Determination of the composition of cementing material left in cultural relics, is of importance not only for Chinese architecture history and art technology history, but also for maintenance of endangered cultural relics and development of modern green cementing material. High specificity and sensitivity of antigen antibody immunoreaction were utilized. Accurate detection of micro egg white in ancient mortar samples by enzyme linked immunosorbent assay(ELISA), have been realized for the first time. The minimum detectable concentration was 0003%(by mass). The interference from the color of earth itself is avoided, providing the effective detecting techniques for the determination of the composition of ancient tabia mortars and other remains.