[Purpose/significance] The research assessmentis considered as an effective means of research management, but its implementationis usually controversial. Clarification of research assessment from a basic theory perspective could help the evaluatorsand researchers well interpret and wisely employ appropriate indicators and tools in practice, fostering a virtuous circle for research assessment. [Method/process] This paper aimed atclarifyingthe reflections of research assessmentfrom five aspects: development of science, peer review, review of representative works, common misunderstandingsabout quantitative evaluation, and transformation of traditional literature retrieval system, based on the basic theoriesinresearch fields of scientometrics and science of science. [Result/conclusion] Itisthetruththatbasic theoriesinscientometrics and science of science fields have played and will continue to play an important supporting role in the improvement and implementation of research assessment.