Allergic diseases with their early onset and clinical complexity have been increasing in prevalence worldwide and have now become a serious public health problem. The laboratory diagnosis of allergen is pivotal for clinicians to the identification of the environmental causes of allergic diseases, in addition to provide a rational basis for personalized treatments. The laboratory diagnosis technology of allergens includes in vivo test (Epicutaneous skin test) and in vitro testing (Quantitative measurement of circulating IgE antibody). Once a reasonable suspicion is established, a laboratory confirmation with a high accuracy can be obtained utilizing a proper laboratory diagnosis technology (in vivo tests and/or in vitro test), the right types of allergens (seasonal or perennial allergens) as well as a complete medical history. Component resolved diagnostics (CRD) utilizes individual natural or recombinant allergenic components that are contained in the whole complex allergen source. By focusing on the individual major or minor allergens and controlling for allergen concentration, CRD promises a more precise and individualized (clinically relevant for the patient) measurement of allergen-specific IgE antibodies. Therefore, this article reviews the application status, clinical interpretation and latest research progress on laboratory diagnosis technology of allergens in children allergic diseases.