PURPOSE: To provide diazo photosensitive paper having high image density, high sensitivity, satisfactory surface properties free from unevenness in coating with a diazo photosensitive liq. and satisfactory preservability.

CONSTITUTION: A precoat layer contg. 50-70wt.% starch particles is formed on a substrate by 1.5-5.0g/m2 and a diazo photosensitive layer contg. silica is formed on the precoat layer to obtain the objective diazo photosensitive paper. Since the precoat layer captures the silica with an adsorbed diazonium salt on the surface, the penetration of the diazonium salt into the substrate or the precoat layer is inhibited and the lowering of image density and sensitivity can be prevented. The absorbing property of the precoat layer is made uniform and the occurrence of unevenness in coating can be prevented.