To explore the effect of concrete binary mixed metakaolin and silica fume on the resistance of hydrochloric acid， the specimens were prepared according to 5% metakaolin and 5%， 10% or 15% silica fume by weight of total cementitious materials， and the immersion test of hydrochloric acid was carried out. The effects of corrosion on the thickness of the damage layer， pore structure and hydration products of concrete were investigated by ultrasonic， mercury intrusion porosity （MIP）， X-ray diffraction （XRD）， thermogravimetric analysis （TGA） and scanning electron microscopy （SEM）. Moreover， the relationship between the thickness of the damage layer and the pore structure is compared and analyzed. The results show that M5S5 has the best acid resistance based on compressive strength， splitting tensile strength and flexural strength. The thickness of the damage layer is negatively correlated with ultrasonic velocity， and positively correlated with porosity， average pore size and total pore area. The combination of metakaolin and silica fume can improve the acid resistance of concrete. However， the increasing content of silica fume slightly reduces the improvement effect.