Abstract: Mr. SUN Zhang-ding (1899-1976), an expert in forestry in the Republic of China, had been engaged in teaching and research work in university and institutes, and he had also been devoted to forestry administration and technology promotion in forestry agencies. Especially, he took part in the forest resources inventory in the provinces of Sichuan, Hunan and Guizhou, and worked as local folk forestry supervisor in charge of the forestry construction in Hunan and Hubei provinces. He composed many research works. In the biography Mr. SUN Zhang-ding written by Mr. WANG Xi-zhong,16 of Mr. SUN’s works were listed. According to the newly-discovered manual scripture The Forestry Works by Mr. SUN Zhang-ding and by reviewing journals and newspapers in the Republic of China, I found that there were as many as 29 pieces of his works. In this paper, newly discovered books by Mr. SUN Zhang-ding are added to his list, and his works are introduced and evaluated.