The amounts of HCl and alkali metal vapor in hot gas are generally small, compared to those of sulfurcompounds, nitrogen compounds, and particulates. Nevertheless, the removal of these contaminants is verybeneficial in any power plant because of corrosion when they contact metal components. In this paper, theexperiments by single and combined methods were carried out to remove HCl and alkali metal vapor in hotgas cleaning. The results indicated that all sorbents for the removal of HCl vapor can reduce HCl to less than1 mg/m
3 at 550
C; sorbent E1 self-prepared by montmorillonite and Mg(OH)
2 presents the highest chlorinecontent and the longest breakthrough time. It is found that the activated Al
2O
3 having a specific surface areaof 258.3 m
2/g displays the highest efficiency for the removal of alkali metal vapor at 840
C. The tests indicatethat the removal of alkali metal vapor with activated Al
2O
3 is not a physical adsorption process in the presenceof moisture. A multifunctional four-zone reactor system was developed for the combined removal of HCl andalkali metal vapor, and the results show that the removal of HCl and alkali metal vapor with high efficiencyis feasible by solid sorbents in a reactor.