The photothermographic(PTG) imaging materials are the kind of digital hardcopy imaging medium usually used in diagnostic medical field. The hardcopy image was obtained by thermal printing process using driving laser or thermal print head on PTG materials based on electronic data. Toner, as the most important of components to provide better image quality, is a compound could modify the shape and size of Ag0 particles to correct the image color from yellow-brown to black in thermal imaging process. In the paper, the effect of nicotinic acid as a new toner on PTG based on silver benzotriazole as silver sources had been studied. The results indicated that development of silver benzotriazole PTG materials was promoted by the introduction of nicotinic acid and the function of nicotinic acid was influenced by the pH of the silver benzotriazole emulsion and the amounts of nicotinic acid. The promotion of nicotinic acid was strengthened with the pH in system increased in the condition of the same amounts of nicotinic acid added in PTG emulsion. The best promotion could be obtained in the case of the mol ratio of nicotinic acid to silver benzotriazole 0.1 and value of pH in emulsion about eight. The IR spectrum data implied that the silver complex, which was supposed to be easy to transmit silver ions from silver salt to development center, was produced by nicotinic acid and silver benzotriazole.