Abstract: To enhance the yield and quality of tar in pyrolysis technology regulated by internal components, the effect of a hydrogen-rich atmosphere on tar production and its mechanism were systematically investigated. Using Naomaohu coal and walnut shell biomass as feedstocks, pyrolysis experiments were conducted in an internal component-regulated reactor under both hydrogen-rich and nitrogen atmospheres. The experimental results showed that the hydrogen-rich atmosphere significantly increased the yield of pyrolysis tar, and the yield of tar increased continuously with the rise in pyrolysis temperature. Compared with the N? atmosphere, a hydrogen-rich atmosphere improved the tar yield of Naomaohu coal by 14.7% to 16.5% under different temperature conditions. When the pyrolysis temperature reached 1000 °C, the tar yield achieved by the hydrogen-rich atmosphere coupled with the internal component-regulated pyrolysis technology reached 91.5% of the theoretical maximum yield. At the same time, the tar quality was significantly improved, with the content of light components (boiling point below 350℃) increasing from about 54% under the N? atmosphere to about 58% under the hydrogen-rich atmosphere. Moreover, during the biomass pyrolysis process, the hydrogen-rich atmosphere also showed a notable promoting effect, with the tar yield increasing by 2.84 wt.% at 1000 °C. Translate the effect of using a hydrogen-rich atmosphere coupled with internal component regulation to improve the yield of pyrolysis oil in biomass pyrolysis. Additionally, the hydrogen-rich atmosphere shows a similar trend in the relative content of various components of bio-oil to that of Naomaohu coal pyrolysis oil. This study provides theoretical basis and technical support for improving tar quality through pyrolysis technology regulated by internal components.