ABSTRACT The understanding of thermal behaviors of inherent alkali and alkaline earth metals (AAEMs) is significant for the reduction of corrosion and deposition and further utilization of by-products. In this paper, effects of temperature (400–900 °C), retention time and secondary reaction on the release and distribution of AAEMs in products and evolution in the char were systematically investigated during fractional tissues of corn stalk pyrolysis. Results reveal temperature is the crucial factor for AAEMs release and transformation. < 700°C, AAEMs, except Na, was metastable in char. However, ion-exchangeable AAEMs slightly convert by interaction with oxygen-containing active sites. At 900°C, release of AAEMs increased abruptly by the form of salts steam. And spherical or broken bubbles on the molten surface, especially for > 700°C, impenetrate polymer channel and promote the entrainment of AAEMs by aerosol. The enrichment of Si and Al retain them again in the char by the form of acid-soluble and insoluble matter. Compared to char pyrolysis stage, release of AAEMs during devolatilization was lower. Hence, collision probability of AAEMs with oligomers was less likely that leads to inclinable distribution in the aerosol. Simultaneously, longer traveling time-restricted escape from the path of particle clearance.