Objective To reduce health-related threats of heat waves,interventions have been implemented in many parts of the world.However,there is a lack of higher-level evidence concerning the intervention efficacy.This study aimed to determine the efficacy of an intervention to reduce the number of heat-related illnesses.Methods A quasi-experimental design was employed by two cross-sectional surveys in the year 2014 and 2015,including 2,240 participants and 2,356 participants,respectively.Each survey was designed to include one control group and one intervention group,which conducted in Licheng,China.A representative sample was selected using a multistage sampling method.Data,collected from questionnaires about heat waves in 2014 and 2015,were analyzed using a difference-in-difference analysis and cost effectiveness analysis.Outcomes included changes in the prevalence of heat-related illnesses and cost-effectiveness variables.Results Relative to the control participants,the prevalence of heat-related illness in the intervention participants decreased to a greater extent in rural areas than in urban areas(OR=0.495 vs.OR=1.281).Moreover,the cost-effectiveness ratio in the intervention group was less than that in the control group(US$15.06 vs.US$15.69 per participant).Furthermore,to avoid one additional patient,the incremental cost-effectiveness ratio showed that an additional US$14.47 would be needed for the intervention compared to when no intervention was applied.Conclusion The intervention program may be considered a worthwhile investment for rural areas that are more likely to experience heat waves.Meanwhile,corresponding improving measures should be presented towards urban areas.Future research should examine whether the intervention strategies could be spread out in other domestic or international regions where heat waves are usually experienced.