This paper presented quantitatively the results of an experimental investigation on the influence of either mineral admixtures, fly ash or GGBS and superplasticizers on micro hardness of aggregate to paste interface.The interface micro hardness values (HV) were tested by a Vickers micro hardness testing equipment.Test results indicated that the addition of fly ash decreased interface micro hardness of the concrete at the early ages.The inclusion of GGBS was found to increase the interface micro hardness significantly when compared to the concrete with fly ash.The addition of fly ash and GGBS compositions was helpful to increase the HV at the later ages, but not useful to improve the HV at the early ages.Kinds of superplasticizers influenced the HV at different curing ages.Aminosulfonic acid based superplasticizer and hydroxy sulphonate condensate superplasticizer were helpful to enhance the HV at the early curing ages and those of concrete with polycarboxylic acid superplasticizer at the late curing ages were higher.